by Richard Lunsford

           In nature, turtle diet varies wildly by species, locality and season. Sometimes even by gender (i.e.: some map turtles). Alligator snappers, RES, female Barbour’s map turtles ( the latter with considerable mollusk intake and specialized large head with crushing jaws vs males being more insectivorous)…a RES or painted turtle in a lush river backwater vs a poorly vegetated cattle pond…the sparsely vegetated and relatively invertebrate-poor days of early Spring vs the abundance of late Summer…all these factors play important roles. What’s more, temperate locality turtles may have a few months of hibernation, rest periods without eating, and when they emerge cool water and scarce prey and vegetation may extend the effective Winter’s fast. Wild turtles generally have more sun exposure and in theory can thus synthesize more Vitamin D3. There’s more to the issue than nutrients (fats, carbohydrates, proteins, vitamins and minerals). There’s also the question of food’s relative proportions and physical characteristics like fiber/roughage content (as when we read high-fiber diets give humans lower colon cancer risk).

             All of which leads to the question: What, how much and how often should I feed my pet turtles? How much and how often is a separate article in its own right, drawing heavily from incomplete knowledge of wild turtle habitat and behavior coupled with anecdotal reports that can’t be demonstrated via scientific research due to the practical limitations involved with experimental monitoring of large numbers of fairly large, long-lived, high-maintenance animals for multiple decades (say, to determine if high-protein diets shorten RES life spans, how often, how much and in what percentage of turtles). And then there is the animal’s activity level to consider.

             Likewise, the question of what to feed turtles is hotly debated and drawn from similar sources. We do have the added luxury of published research listing stomach contents in several species, so we may at least extrapolate from what is found in wild turtles’ bellies (which, of course, can be affected by the durability of food items).

             For this article, I’m breaking down our choices into commercial processed foods, processed natural foods, commercially sold frozen foods, commercially sold live foods, wild-caught live foods, raw & processed meats (including canned pink salmon), and plants. The focus is on common aquatic/semi-aquatic native U.S.A. turtle species’ food choices, and the relative merits & drawbacks of each. I’m leaving box turtles, tortoises & exotics for somebody else. Where my guys’ food preferences are noted, my current turtle collection includes one each of these species: Stinkpot, Mississippi mud, Southern painted (Ben, Bob and Stefan).


A.) Commercial Processed Foods.

I.)                 The Case for Them – The most famous example is Tetra’s product Reptomin. Mazuri is also getting press. Proponents argue that manufactures have researched turtles’ nutritional needs to an extent no individual owner can, have manufacturing methods that achieve via economy of scale what no individual keeper can produce, and market products so nutritionally complete, compact, dry-storable without freezing, widely available and convenient that this should be the dietary staple of pet turtles.

II.)               Concerns:

a.)    Research - No one seems to know just what research methods were used, on what species of turtles, based on what initial data/information, or how long this went on. Worse, some people consider rapid growth a sign of good nutrition, where many keepers fear shell pyramiding, kidney failure and shortened live span with rapid growth. If knowledgeable hobbyists recommend feeding high-protein foods no more than every other day after the first year of life, why does the Reptomin can say feed 2 to 3 times/day in small quantities (without specifying what small quantities are)? Just how certain is Tetra this product contains every last trace nutrient a given turtle needs? Worse, it bills itself as a highly nutritious diet for “…aquatic turtles, amphibians and other water reptiles.” How is a carnivorous frog diet appropriate for a herbivorous adult cooter (which in nature eats high volume low nutrient vegetation, not low volume high nutrient foods)? Mazuri Freshwater Turtle Food has more credible instructions, & their web page gives you a nutrition breakdown: check out: Tom C. noted “...Mazuri products are being used by Zoos, namely, the Fort Worth Zoo. The FWZ has one of the top wildlife nutrition centers. They do constant testing of products and foods they bring in to feed, so I'd say that they are running along the top lines.”

b.)    Target Audience – What turtles is this food made for? RES, probably. A progressively herbivorous omnivore preferring meat when available. One might say Painted turtles are equivalent. So who says it’s right for alligator and common snappers, softshell turtles, mud and musk turtles, map and chicken turtles, etc…? Personal opinion: I think a carnivore diet is more likely to harm a herbivore than an omnivore diet is to harm a carnivore. If I worried about what turtle a food was meant for, I’d worry in the direction of too much protein.

c.)    Constitution – Commercial foods seem to cram an awful lot of nutrition into a small volume (like those t.v. commercials claiming one bowl of Total cereal has your whole day’s supply of vitamins and minerals; that would make sense, if all you ate in a day was one bowl of Total). Natural foods would seem much less nutrient concentrated: vegetation is low nutrient value compared to meat, snails are mostly shells, insects have exoskeletons of indigestible chitin, even earthworms contain relatively nutrient-poor dirt. Turtles are voracious yet keepers struggle with keeping them on sparse diets due to overfeeding concerns. Do you want to feed a high nutrient concentration food?

d.)    Bulk Fillers – so, what ABOUT those indigestible elements like chitinous exoskeletons? Low nutrition vegetation? Fiber? Do they play a role independent of nutrition? If so, where does Reptomin fit in? And what about the fillers used in commercial foods?

III.)            Other Pet Foods – Not nutritionally ‘balanced’ for turtles, not based on turtle research, not likely to have an extensive base of practical real-world use in turtles, and commercially processed foods tend to contain fillers. The fillers may be fine for the animal the food is for, but when you feed it to a radically different animal (dog food to a turtle), well…at least in theory, there could eventually be trouble. Consider the goal; is trout chow supposed to bring long life to trout, or rapid-grow them to adulthood? If the latter, do you want to use it for a very different life form where rapid growth is to be avoided? Better check those ingredients & percentages, friend…

IV.)            Dark-Horse Option: I’ve used Hikari algae wafers (marketed for algae-eating fish like plecostomus) to feed turtles (minority player in diet); believe it or not, my stinkpot and Mississippi mud love them. Yes, that’s right, these won’t-touch-a-plant-at-gunpoint mud and musk guys really chow down on these. One way to get plant matter into your mud/musk, but still high protein content & uncertain nutritional value (what they actually digest & get out of it).

V.)              My Take: Use Reptomin, Mazuri or another strong brand name commercial diet as a regular at least minority staple of the diet to insure a holistically complete diet. At the very least, provide lots of fresh greens (Romaine lettuce, Anacharis, etc…) to supplement it for omnivores & herbivores. I don’t recommend feeding over once daily the first year of life, or over every other day thereafter. I use Reptomin about every other day along with frozen foods. Occasionally I offer T-REX Aquatic Turtle Dry Formula (no special reason besides variety, brand name & it was on the shelf) and Hikari Algae Wafers. I plan to try Mazuri.


B.) Processed Natural Foods.

            Examples include freeze-dried foods and those otherwise preserved such as Zoo Med’s ‘Can O’ Crickets,’ and ‘Can O’ Grasshoppers,’ and those sold in a preserved gel form (Tetra Nature’s Delica line).

I.)                 The Case for Them: Can be bought at pet stores. Evidently can be stored in closed containers a long-time without refrigeration. Freeze-drying is believed to kill parasites, in effect disinfecting the foods. It removes water by freezing then converting the water from solid state (ice) to vapor without an intervening liquid phase. Thus, food retains its original shape. And since most minerals and some vitamins are water soluable, this technique avoids vitamin ‘wash out’ that removing liquid water can cause. The processing methods used to produce the ‘Can-O’ line aren’t known to me. The methods of producing the gel form foods aren’t known to me, either.

II.)               Nutrition – Many freeze-dried foods (like Tetra’s freeze dried shrimp turtle treat) are intended to be treats, not dietary staples. Thus, they may provide protein, carbohydrates and perhaps fats but aren’t likely to provide the full range of needed nutrition.

III.)            Processing – Freeze-drying is designed to preserve nutrients by avoiding leaching from water drainage. The exact processing methods used to produce pet food & the extent to which they may compromise (a.k.a. destroy) some nutrients I don’t know.

IV.)            Prey Experience – Many turtles eat freeze-dried and gel-encased prey with gusto; some owners wonder if it tastes as good as frozen or live prey. Obviously there’s not much ‘thrill of the hunt.’

V.)              Nutritional density – freeze-drying reduces volume greatly, which may lead one to ask just how much of such food to give a turtle, and whether it would be better to give food with full original mass/volume (for satiety reasons).

VI.)            Mess – freeze-dried foods tend to be fairly clean but the gel-based prep.s can be quite messy when turtles attack. Okay in under-stocked large enclosures or those where water is changed very often or the turtles are fed in a separate container.

VII.)         Examples:

Can O’ Crickets: 20.0% Crude Protein (min), 5.0% Crude Fat (min), 1.0% Crude Fiber (max), 3.0% Crude Ash (max) and 75.0% Moisture content (max). The Cricket species used is farm-raised Gryllus lennaeus.

Can O’ Grasshoppers: 20.8% Crude Protein (min), 2.2% Crude Fat (min), 4.4% Crude Fiber (max), 1.1% Crude Ash (max) and 71.2% Moisture content (max). The Grasshopper species is farm-raised Valanga nigricornis.

Tetra Nature’s Delica Fresh Tasting Treat: Brine shrimp, blood worms or Daphnia suspended in a nutrient-rich gel; fairly pricey, but the box comes with a lot of individually sealed feedings (needn’t refrigerate until opened). I’d recommend as an occasional treat for hatchings of a small turtle collection; cost-prohibitive otherwise. Can be a little messy. You can see the product at:

            VIII.) My Experience: Regarding the Can O’ line, my turtles don’t hit the grasshoppers, but my guys are really too small for them. I don’t recall them hitting the crickets hard, either. The Delica line I use once in awhile; it’d be pricey for larger numbers or more than a few adult turtles.


C.) Frozen Foods.

            Examples include blood worms, brine shrimp, Spirulina-enriched brine shrimp, krill, ‘plankton’ (appear to be shrimp larger than brine), squid, mosquito larvae, beef heart and Emerald Entrée’, among others (based on what I’ve bought at PetsMart in Clarksville, TN).

I.)                 The Case for Them: Can be bought at pet stores. Store long-term in freezer. Freezing supposedly disinfects (how cold, how long, how dependably, who knows?). Many believe it gives rich live prey taste & nutritious variety without the parasite & disease-causing germ concerns inherent in live foods. I believe they are not as nutrient-dense as commercial foods, so the turtles may get more satiety from the added bulk. Some hope such diets may offer some trace vitamin or mineral the commercial companies missed. This is especially true with foods harvested from the wild, since the animals are ‘gut loaded’ with their natural diets.

II.)               Expensive – If you have a lot of turtles, you won’t use much frozen food unless you catch it wild & freeze it yourself.

III.)            Nutrition – Designed for fish, not turtles. No one food designed or intended to be nutritionally complete for anything. You need to mix and match, and vary with other foods (like Reptomin, Romaine lettuce, etc…). Some items, like blood worms, are known to be lousy nutrition choices for a one-food diet. Some foods are produced under conditions we know little of (like, what are commercial blood worms fed?). I do recommend if you use Brine Shrimp use the Spirulina-enriched version if possible, to give a more rounded nutrition profile.

IV.)            Sodium – Brine Shrimp come from high sodium environments. Some frozen foods (like plankton and squid) are targeted to salt-water fish. Who knows how rapidly salt diffuses out of prey into the water? Does your turtle give it time too, anyway? Does anyone know what a high sodium diet does to turtles?

V.)              Wild-Caught Frozen Foods – Some fish contain thiaminase (which breaks down Thiamine (Vitamin B1) and can cause neurological problems) – freezing doesn’t fix & some think may exacerbate the problem. Freezing may kill parasites, but guessing about how cold & how long vary. Wild-caught foods may contain tape worm, fluke, etc…I think 3 months will render food effectively disinfected, but no guarantees. In Practical Encyclopedia of Keeping and Breeding Tortoises and Freshwater Turtles, page 105, A.C. Highfield recommends freezing at least 1 month.

VI.)            Frozen Fish for People – lacking the G.I. tract so not gut-loaded. Lacking the small, edible bones so less calcium. In fact, larger fish product is basically just muscle tissue; not a well-rounded diet. Some fish contains thiaminase, which breaks down needed thiamine. Not recommended (except as rare snack).

VII.)         Unnatural Diet – Just because it’s from nature doesn’t mean your turtle would eat much of it in the wild. Fish are the best example of a food many people love to give turtles (figuring with bones for calcium it’s an excellent choice) when in fact most species of turtles get very little fish in nature. Many people warn against giving fish more than once a week. So, what do we really know about feeding your turtle commercially-bought frozen foods?

VIII.)       My Take – Role in diet is supporting player. Round out with Reptomin & vegetation like Romaine lettuce and Anacharis.

IX.)            Examples from the San Francisco Bay Brand (SFBB) Product Line:

a.)    Bloodworms: Midge larvae, not mosquito larvae. Some people have a powerful allergic reaction to them. It’s my understanding they aren’t very nutritionally rounded & should be a minority player in the diet.

b.)    Mosquito larvae: SFBB’s web site says they have a very high protein and fatty acid profile, triple that of blood worms. My turtles will eat these but seem to prefer shrimp-based foods like Krill better. I’m under the impression these aren’t very well-rounded nutritionally; I’d recommend use as occasional snacks, no more.

c.)    Brine Shrimp: The famous ‘Sea Monkeys.’ Very small shrimp from such high salinity water (lakes) little else can live in it. There’s a concern here; high sodium. See how SFBB produces them at:

d.)    Spirulina-enriched brine shrimp: Spirulina algae supposedly enhance immune system function in some fish. Whether gut-loading with this before freezing is preferable to the algae ‘normal’ brine shrimp would have instead, or how the relative amounts compare, I don’t know. I buy and use this.

e.)    Omega-3 Fatty Acid-enriched brine shrimp: enriched but I believe it made a little oily film in my tank. Also, I believe it lowered the pH in my tank (I’m unsure; other factors may’ve been at work).

f.)      Plankton: Looks like small shrimp, maybe 1 cm long. Different colored than brine shrimp or krill. Took my little guys awhile to warm up to, but they eat it now. SFBB says heavy β-Carotene that brings out color in fish..

g.)    Krill: A shrimp harvested from Arctic waters. Contains high amounts of omega-e fatty acids. SFBB’s web site says contains astaxanthin, a carotenoid responsible for the vibrant colors of tropical fihs. Hot pink cubes. My guys love these.

h.)    Mysis (Oppossum) shrimp: Small salt-water shrimp from Europe. In my experience gives off a large cloud of small particulates. Recommend feeding in separate container.

i.)      Squid: White chunky meat. My turtles like it fine. Marketed for salt-water carnivores, so I’d think maybe high in sodium. Since squid’s relative the cuttlefish is used to produce cuttlebone, supposedly a calcium source offered to turtles, squid might be expected to have significant calcium as well. I have not confirmed this so don’t assume it.

j.)      Beef Heart: Heart is largely composed of cardiac muscle; it doesn’t contain a G.I. tract, so it’s not gut-loaded to contain the vegetation-content one might find in while prey animal. I don’t know how far they’re willing to stretch the definition of ‘beef,’ but Encyclopaedia of Terrarium, page 55 states “Ox heart contains one hundred times more phosphorous than calcium, with only 2 mg calcium per 100 g (3 ½ oz) of meat. Heart also contains virtually no fiber but very high levels of proteins.” It recommends against feeding it to terrarium animals and notes liver has similar problems as well as high levels of waste matter. I would think ox heart would be equivalent to beef heart. Even San Francisco Bay Brand’s web site recommends it play a supplemental role to the primary diet (in fish).

k.)    Emerald Entrée: In my experience, gives off a large cloud of small particulates & makes a mess. SFBB incorporates mysis shrimp as an attractant. Fortified with omega-e fatty acids. Designed for marine fish but marketed for fresh water also. Recommend feeding in separate container.

l.)      Goldfish Food: SFBB makes using Anacharis, zucchini, spinach, carrots, romaine lettuce, brine shrimp and is fortified with stabilized Vitamin C and made to sink. Spinach and carrots are high in oxalic acid (Encyclopaedia of Terrarium, pages 56-57) which can bind up calcium so I wouldn’t use a lot of this for turtles.

m.)  Freshwater Multipack: SFBB’s ‘combo. pack’ of Discus Delight, Emerald Entrée, Bloodworms and Spirulina-enriched Brine Shrimp.


D.) Live Foods.

            2 Types: Commercially sold (guppies, rosies, comets, ghost shrimp, crickets, meal worms, wax worms, pinkie mice, earthworms) and wild-caught (crawdads, perch, slugs, grasshoppers, crickets, earthworms, ‘field plankton,’ etc…).

I.)                 The Case for Commercial Feeders – Can be bought conveniently, fairly cheap, thought to ‘taste good,’ high enough moisture content to give satiety, give the thrill of the hunt, can be used to mimic part of natural diet, and some feeders will actually clean the tank for you. You can gut load feeders with varied things, and fish have bones for calcium. If the feeders are produced without contact with turtles, then turtle parasites with indirect life cycles (i.e.: tapeworms) have no change to infect the feeders.

II.)               The Case for Wild-Caught Feeders – may actually be part of natural diet. May be gut-loaded with a larger variety of vegetation that’s a natural part of the turtle’s diet. Can often be caught in large quantities for free.

III.)            Remember: Pet Stores may not feed feeders. At least gut-load with something! Even fish flakes are much better than nothing.

IV.)            Consider breeding your own, if practical; they’ll be in better condition & more nourishing.

V.)              Parasites – many people speak of these with feeder comets, but few specify what parasites or whether they can infect turtles. Still, live food can transmit parasites freeze-drying or freezing would kill. It’s unclear just which feeders carry which parasites, but Goniobasis snails are known to carry lung flukes that infect Loggerhead musk turtles, for example. Turtle tapeworms have to come from some indirect host.

VI.)            Disease – Another concern hypothetically raised but potentially real. Crustaceans including crayfish & crawdads are associated with a form of bacteria known as Beneckia chitinovora linked to a form of shell rot.  Frye (1991) mentioned they can harbor a variety of pathogens that can cause various problems, one being bacterial shell rot. (Source for this being Reptile Medicine and Surgery by Dr. Mader).


1.)    Guppies – Vertebrate containing bone for calcium, easily gut loaded with fish fakes, cheap & widely available, eat scraps & a little algae in the tank, can be had in varied sizes, easily bred in your tank (live bearers). On the other hand, fish makes up a very small portion of most wild turtle diets so not a very ‘natural’ staple, many turtles can’t catch so you often have to kill them, once they breed they can be hard to eradicate from large enclosures, and commercial product is often kept in poor conditions and may be unfed & malnourished. Not all turtles like the taste.

2.)    Rosies – as per guppies, but much larger. Egg layers, so breeding isn’t as simple nor are they likely to overrun the tank. Gaudy orange color; your taste may vary. Some turtles may not be easy to catch, so be ready to kill. I’m not clear as to whether they’ll eat any algae. I’ve turtles prefer their taste to guppies.

3.)    Comets – as per Rosies, but fatter (more likely to require shredding with claws; more likely to foul water) and many think fatty (rumored to have unhealthy fat levels). If not eaten, can grow rather huge. You must be ready to kill what’s not caught. Rumored to be parasite havens, but it’s not clear that those parasites are or whether they will affect turtles. Goldfish contain thiaminase.

4.)    Ghost Shrimp – Good janitors, lack the dangerous claws of crawdads, easy enough to catch but hard enough to make it interesting, thrill of the hunt, evidently taste good, and have an indigestible chitin exoskeleton (for bulk without high nutrition). Lack bones for calcium. associated with Beneckia chitinovora, linked to shell rot (per IV.), above). Sold in pet stores, but not as common as guppies, rosies and comets. Small crustaceans are a significant part of some turtles’ diets. 

5.)    Crayfish – as per ghost shrimp, but harder to get commercially, can get much larger, often cost much more, can be dangerous due to claws if size anywhere near turtle’s, can be predatory to tank mates or eat plants, and wild-caught could harbor parasites we just don’t know much about (pure speculation). If not cleaned, they or water on them could harbor tiny turtle parasites/eggs. Not recommended (unless washed thoroughly in chlorinated water or frozen).

6.)    Earth Worms – Good protein source, contain red blood (and so in theory hemoglobin, and thus iron), can be gut-loaded with whatever you put in their soil, and surprisingly despite lacking bones the calcium/phosphorous ratio isn’t bad. Try to avoid worms raised/kept in manure or caught in pesticide/herbicide sprayed areas. Red wrigglers are smaller & handier for little guys than night crawlers. You can breed your own worms, but they’re cheap.

7.)    California Blackworms – They’re actually red, extremely thin, and come in a big red ball with a refrigeration pack. Kinda like a clump of blood worms, but much thinner and longer. You can buy these at: They are not black tubifex worms!!! These are marketed as very tasty fish food, and unlike tubifex worms they are popular for live rather than freeze-dried use. In nature they are an aquatic equivalent to the earth worm. Learn more than you ever wanted to know about them at: I bought a half-pound once; sized kind of like one of those small hamburger meat packs at the grocery store. Can be kept alive a few days in fresh water in the refrigerator, but realistically, plan to use within 3 days. I haven’t specifically heard of any parasite problems, but theoretically the potential is there. I’ve used as a specialty treat; my guys ate’em, but didn’t go wild or anything.

8.)    Live Tubifex Worms – Allegedly often come from filthy conditions, high disease risk, not recommended live!!! The Krib has a nice little summary at:

9.)    Aquatic Snails – Mollusks are much-loved by many mud and musk turtles; some map turtles, particularly females with large heads such as Barbour’s, eat many mollusks. Turtles litter the tank with shell bits. Snails clean the tank until eaten; generally survive well until then, so there’s the ‘thrill of the hunt.’ I recommend captive-bred in ‘turtleless’ enclosures; Loggerhead musk turtles feeding on the wild snail Goniobasis are often heavily parasitized by the lung fluke Heronimus mollis (Cox, W. A., S. T. Wyatt, W. E. Wilhelm, and K. R. Marion. 1988. Infection of the turtle, Sternotherus minor, by the lung fluke, Heronimus mollis: incidence of infection and correlations to host life history and ecology in a Florida spring. J. Herpetol. 22:488-490). You can read about snail shell constituents at (assuming the apple snail is representative). According to this page, at least the apple snail shell has calcium carbonate crystals. Another link,, indicated calcium carbonate is found in other snail shells. I don’t know how well turtles utilize snail shells for calcium, but in theory the potential is there.

10.) Terrestrial Slugs – Mollusks; basically snails without shells. I don’t have a lot of great info.; I do know a number of aquatic/semi-aquatic turtles will eat them. Parasite risk uncertain; may be safer than wild-caught aquatic snails, but that’s a guess. I would catch mine away from natural water bodies where they’re less likely to be exposed to aquatic turtles’ feces, etc…

 Special Note on Insects: Insects have a calcium to phosphorous ratio between 1:3 and 1:15; this should be ‘corrected’ to about 2:1 (per Encyclopaedia of Terrarium).

 11.) Crickets – Commonly available & there are even gut-load prep.s for them, as well as non-liquid water sources. Can be had as adults or pin heads. Could ‘nibble’ turtles on land or basking spots.

12.) Grasshoppers – Often enjoyed & likely gut-loaded with vegetation, so may benefit primarily carnivorous turtles. Nutritional value unclear; I’d guess similar to a cricket. Many sizes available; mostly a wild-caught Summer/Fall food. Be wary of pesticides; many fly & can cover a lot of ground, & thus one you catch maybe got pesticide exposure in the neighbor’s garden.

13.) Caterpillars – Turtles don’t like hairy ones & some sting; don’t use unless you know what you’re doing. Generally have to be wild-caught. Some people have Catalpa trees that produce the legendary catalpa worm, much loved by fishermen. I haven’t tried these in so long I don’t recall how well they work.

14.) Water Bugs – the giant water bug can bite; if you use water bugs; use only small ones. My Southern Painted was surprisingly adept at catching these. Only available wild-caught, and with ‘wild water’ you may (theoretically) pick up parasites (or their eggs) like hook worms, round worms, tapeworms, etc...and introduce them to your tank. Not recommended.

15.) Cockroaches – Many animals have difficulty eating the wingless type per Encyclopaedia of Terrarium, page 47. I would imagine turtles could do so.

16.) Meal Worms – Not very nutritious; high proportion of fat; about 15 times more phosphorous than calcium; hard, indigestible shells may cause blockages; often swallowed alive & can damage stomach & intestine walls (all meal worm info. from Encyclopaedia of Terrarium, page 46).

17.) Wax Worms – I’m not knowledgeable about these; I believe I’ve heard they’re not that great a food item, so I’d use as a rare snack if at all. I’ve heard they’re high fat; check out and click on the nutrition info. button; they’re 62% moisture, 20% fat and 16% protein.

18.) Pinkie (and larger) Mice – Possible ethics issue; feeding higher life-forms than necessary. Pinkie mice should be fed as soon as possible after removal from the mother, since the mother’s milk provides valuable nutrition & it’s only then the calcium/phosphorous ratio is 1:1 (Encyclopaedia of Terrarium, Page 52.)

19.) Frogs, Toads, Newts & Salamanders – Never offer an amphibian from outside the turtle’s native range; the turtle has neither instincts to avoid nor adaptive poison resistance to deal with the prey. Kory Steele pointed out that even amphibians within the turtle’s native range are not perfectly safe; the turtle may have no instinctive avoidance of terrestrial forms (like tossing a spotted salamander to a RES), parasite risks are a possibility, and even some water-dwellers can be troublesome (the pickerel frog is well-known for toxicity yet looks like a leopard frog!). Kory noted even ranid frogs not noted for toxins as adults (like bull, leopard & green frogs) may have toxins in the tadpole stage. He also mentioned the awful way turtles kill frogs; I’ve seen it & concur. I do not advocate the feeding of amphibians to turtles. It can be done but it is risky and there does not seem to be a clear need.

20.) Tadpoles – Be wary. Technically there’s a parasite risk. Tadpoles may produce toxins just as adult amphibians may. And some amphibian populations are in serious decline, and the added burden of human predation can destroy thousands. On the whole, probably not a good idea. See 19.), above.

21.) Wild-caught fish (perch, etc…) – vary as to whether they contain thiaminase (see Appendix I, section III for link to a table). Significant parasite risk, but details uncertain. I recommend freezing first; thaw thoroughly before use. Any fish too large to be swallowed will be shredded, fouling water fast. Any fish so large you only feed parts is less nutritionally complete.


E.) Raw & Processed Meats:

            There are many reasons why these are a dismal choice as anything but a rare treat.

1.) Unless fed in small bits, turtles shred meat & release juices & bits into the water; fouling can be very rapid. Chop finely enough to easily swallow whole or feed in a separate container.

2.) Many meats sold for human consumption are basically skeletal muscle with some vascular, nerve and connective tissue. No G.I. tract, no nutritious gut contents, no option to gut-load. In other words, severely imbalanced in favor or protein at the expense of other nutrients.

3.) Raw chicken can carry Salmonella, a disease organism of humans. While there is debate over how prevalent Salmonella is in turtles to begin, loading them with a fresh supply seems injudicious.

4.) Exception: Tom Coy has found canned pink salmon to tempt reluctant turtles to eat, and this should be kept in mind. I have found the white meat squeezed from the tails of crayfish to have similar power.


F.) Plants:

            Plants pose many challenges as a primary food-stuff. Human vegetarians used to worry over such issues as incomplete proteins (individual plants allegedly did not contain all 20 naturally occurring amino acids) and the belief the body didn’t well-utilize amino acids from incomplete protein meals, leading to a perceived need to combine complementary plants, and designing an appropriate vegetarian diet for a person was involved. At least in humans, this view has been contested; see the discussion at: So it looks like incomplete protein worries were way over-blown. But designing a holistically complete vegetarian diet for a vastly different species? Please. Refer to Section H. (below) re: tortoises, where this is a critical concern. Although adult RES and Cooters are largely herbivorous, most hobbyists will rely on products like Reptomin & other ‘meat’ type foods to insure adequate nutrition. None-the-less, almost all turtles (even snappers) should at least occasionally be offered vegetation, and for the naturally vegetarian or largely vegetarian it should make up a hefty portion of the diet.

            Some Issues:

1.) Poisonous Plants: Appendix I, Section IV links to a list. Be Careful of Poisonous Plants. Water Hyacinth good. (Terrestrial) Hyacinth bad (poisonous).

2.) Oxalic Acid: Avoid or seriously limit plants that bind calcium via Oxalic Acid: Spinach, Broccoli, Carrots, Parsley, Rhubarb (per Encyclopaedia of Terrarium, pages 56-57).

            3.) Nutritional Value: It’s said iceberg lettuce has very little nutritional value, whereas Romaine lettuce has Vitamin A.

            4.) Fruits with high citric acid can in theory change gut pH, leading to changes in intestinal flora (at least, I think I read that somewhere). On a more practical note, in Practical Encyclopedia of Keeping and Breeding Tortoises and Freshwater Turtles Page 106 re: herbivore diets, Highfield recommends fruit be used sparingly & notes over-ingestion can cause high sugar levels in the gut & thus dangerous colic, and appears to encourage parasite proliferation, especially flagellates. Even though he listed tortoise species as his example herbivores, I still think about this when I read forum postings from people who give their RES bananas and such.

            5.) Important Advisory: in Practical Encyclopedia of Keeping and Breeding Tortoises and Freshwater Turtles (pages 106-107) A.C. Highfield discusses the issue of pesticide residues on commercial produce, and demonstrates there’s a lot more exposure than you think; some residue is left on the product you buy, and few humans consume as much relative to their size as many turtles over extended times. He recommends you seek out certified organic produce if you rely upon store-bought produce.

            6.) Dandelions have good calcium content; watch for pesticides/herbicides!

            For Plant Matters links, go to Appendix I, Section IV.

            For a useful table of plant nutrition & a hatchling tortoise-centered discussion, go to

            7.) Forum regular Wendy provided us some of her plant choices:

            Water Plants

·        Water Lilies

·        Water Hyacinth

·        Duckweed

·        Anachris

·        Water Lettuce

·        Water Fern

·        Pondweed

·        Water starwort

·        Hornwort

·        Water milfoil

·        Frogbit

“The ones they like best are the Lilies, Hyacinth, and the Water Fern,” – Wendy.


·        Zucchini

·        Squash

·        Collard Greens

·        Beet Leaves

·        Endive

·        Romaine

·        Red Leaf Lettuce

·        Kale

·        Escarole

·        Mustard Greens

·        Dandelions

“This is what I basically feed my Iguana, so I also give some to the turtles. Hope it helps some,” – Wendy.


G.) Supplements:

            So what about nutritional supplements? I break these down into 4 categories:

            1.) Multivitamin Supplements – Necessity debatable, but not a bad idea, actually. You cannot duplicate the vast range of a wild turtle’s diet. Even if you could duplicate the prey items, you could not duplicate the plant material in the digestive tracts of the wild prey. This is one more way to hedge your bets. Making them stick to food in water is another story. You may be able to soak some into food & hand-feed it to the turtle. I have not used these.

            2.) Man-made Calcium Supplements – If the calcium to phosphorous ratio should be around 2:1 and you feed a lot of foods (like feeder insects) who have a poor ratio (it’s the ratio; not just the absolute calcium amount), supplements sound intelligent, yes? But examine your turtles’ diet before deciding it’s necessary, especially if you use cuttlebone.

            3.) Man-made Vit. D3 Supplements – Although you’ll read that Vit. D3 isn’t well-absorbed via the G.I. tract & is rather manufactured in the body under UV-B exposure, you’ll see oral supplements (like this one from T-Rex: Solar Drops Liquid UV-B). D3 is necessary to utilize calcium. It’s normally produced when UV-B (a component of sunlight but not light bulbs except specialty bulbs such as Reptisun 5.0) hits precursors in an animal’s body. Note #1: Glass blocks UV light. Note #2: Commercial UV-B bulbs lose UV-B effectiveness some time after 6 months (so replace). Note #3: So-called ‘full spectrum’ bulbs aren’t thought to give much UV-B; if it doesn’t say UV-B, it’s not UV-B. Note #3: You can overdose D3. Check out this article on its effects in birds: Calcium, Phosporous and D3 in birds. Note #4: Some turtles grow up in indoor captivity & no UV-B bulbs or sunlight exposure without supplements for years with no evident ill effects. Some other reptiles demonstrate deformity or impaired growth in similar circumstances. In Practical Encyclopedia of Keeping and Breeding Tortoises and Freshwater Turtles page 90, A.C. Highfield described an experiment he & colleagues undertook comparing tortoises reared under mostly incandescent lighting with calcium & Vit. D3 supplements (who did well) and those reared under extensive UV and full spectrum exposure & calcium but not D3 supplements (who got symptomatic later; this was traced to the reduced UV production of such bulbs as they age). I remember reading somewhere that UV-B bulbs use a special coating to produce the UV-B, and this coating breaks down in the process. Therefore, if you rely on UV-B lighting, change those bulbs somewhere between 6 months and a year (or so I’ve heard). Remember that a standard tortoise diet is far different than an omnivore’s; how much Vit. D3 omnivores/carnivores get in the diet I don’t know, but I suspect it’s a lot more than tortoises get.

            4.) Cuttlebone – Derived from a marine mollusk, the cuttlefish, related to octopi and squid (learn about it at Cuttlefish). Marketed as a calcium supplement for pet birds. It contains calcium carbonate, sodium chloride, calcium phosphate and magnesium salts, and you can read more about use in birds at Cuttlebone Discussion. For a constituent breakdown and discussion, take a look at this Bird Talk Cuttlebone Article. It’s been reported turtles can choke on the hard backing. Many turtle owners peel off the hard backing and break into small pieces, putting some in the turtle tank for consumption as a calcium supplement. Calcium carbonate should be utilizable by turtles. It’s an in-exact science re: how much, how often, whether it should be fresh or allowed to sit in the tank (and how long), whether you can ‘overdose’ calcium, etc… It’s a heck of a lot easier than trying to gut-load a cricket.


H.) A Special Note about Tortoises & Other Special Cases:

            This article is limited in scope; it does not cover the dietary needs of tortoises and some foreign or specialty turtles like alligator snappers, mata-mata turtles, Chitra chitra, and so forth. Tortoises are far & away primarily herbivorous, moreso than even such ‘herbivores’ as RES and cooters. Their digestive systems are specially adapted for a vegetation diet, and not well adapted for meat-based foods. Their organ systems & general metabolism are likewise not designed to properly handle high-protein diets. For a tortoise dietary discussion, I recommend A. C. Highfield’s Practical Encyclopedia of Keeping and Breeding Tortoises and Freshwater Turtles (and for a useful table of plant nutrition & a hatchling tortoise-centered discussion, go to here). Some turtle species (i.e.: mata-mata, Chitra chitra softshells) are such ‘specialty’ species their care should not be wholly based on a generalist article like this one. Issues such as fish ratio in the diet may be very different for specialty turtles than most semi-aquatic/aquatic turtles. For example, not all fish contain thiaminase. Perhaps a mata-mata’s natural prey usually don’t, but the feeder comets you’re using do. There are real issues here. I do not have practical hands-on experience with exotics.


I.) Conclusion:

            So, what should feed your turtle? Tom C. noted the importance of trying to reproduce the nutritional content of food in a turtle's natural habitat instead of trying to replicate the food itself (which you will never do). Many people recommend feeding a variety. Some recommend sticking to commercial foods due to parasite risk & holistic nutrition concerns; others recommend heavy supplementation of commercial diets in case the manufacturers missing anything important, to add bulk & fiber, to provide varied taste and for the thrill of the hunt (live prey).

             I can’t give you the definitive word on what to feed your native U.S.A. semi-aquatic/aquatic turtles. For herbivorous & omnivorous species, I recommend offering leafy greens daily. Organically-produced would be well-advised. Notice I said leafy greens (romaine lettuce; Anacharis; dandelion leaves), not bananas, apples, etc… Look at natural RES/painted habitat & you’ll see lots of green leafy vegetation, but not much imported fruit. For carnivores such as mud/musk and snappers, I say offer some greens anyway, and if they never eat any, make sure plant matter gets into the food they do eat. For me, Hikari Algae Wafers, Spirulina-enriched brine shrimp (frozen), and whatever vegetation is in the guts of my feeders is important, as is the plant-based contribution to commercial food diets. 

            I recommend giving meat-based/high-protein foods roughly daily (and no more) the first year of life, and from every other day to twice weekly thereafter (depending on whether you’re feeding a carnivore or herbivore (say, stinkpot vs cooter). For part of that, I recommend brand name commercial food; Reptomin, Mazuri, etc… For the rest, a mix of frozen fish foods and live prey.

             For my live prey, I breed various snails, buy feeder ghost shrimp once weekly, pick up and gut-load feeder crickets once or twice monthly, offer feeder guppies maybe monthly, catch live slugs by my house occasionally, & pick up red wrigglers at a bait store or a night crawler after a rain, etc…

             Make sure you get plenty of calcium in there!

             Understand; I have 3 little turtles. I can afford to use expensive frozen food from PetsMart. Imagine what it’s like for Tom C., with a large collection. If I had to feed a large collection, I would:


1.) Search for bulk sale turtle food; Tom C. uses Mazuri.

2.) I’d make my own; check out this recipe from Dr. Pritchard's book, Encylopedia of Turtles, that Tom C. lists at:

      3.) Buy a lot of Romaine lettuce; it’s cheap.

      4.) Pick a lot of dandelions where herbicide & pesticide aren’t an issue.

      5.) Buy some fish traps, & keep an eye out since the little ones I’d want may be below legal limits; watch out trapping in ponds where cattle are (in case of pesticides on the cows) or there’s agricultural run-off. These fish would be frozen in small cartons or zip-lock bags for at least one month.

      6.) Buy a seine net & take a friend to a small pond back in the woods somewhere, away from cattle and agriculture. Basically, a seine net looks like a volley ball net strung between 2 hand-held posts, and with one guy at each end, it’s drug along the bottom of the pond, sweeping toward the bank. Tends to produce massive numbers of crawdads, some fish, and I’ve even seen decent numbers of salamander larvae (the last I’d throw back; conservation & amphibian toxin issues). Careful with fish under legal limit size. I’d freeze this food at least one month, like I said in 5.), above. Check out seine nets at: (scroll to bottom of page). I haven’t bought from them, but they’ll let you customize it by size.

      7.) If practical, start a large compost pile & seed with earth worms.

      8.) Think twice before raiding wild plants; yeah, if water hyacinth is in the local lake and your turtles like it, great, but what about leeches, parasite eggs/larvae, etc..? If you use a lot of water washing it thoroughly, are you saving much money vs romaine lettuce?

      9.) Consider a back yard garden. Fresh is much better. In Practical Encyclopedia of Keeping and Breeding Tortoises and Freshwater Turtles Page 91, Highfield notes that lettuce loses 50% of its Vitamin C within 30 minutes of being harvested. Remember that those plants you buy still have living cells; that’s why some stores use sprayers to give them water. And those living cells are consuming nutrients.


Keeping It In Perspective:

      Many turtles are generalist omnivores (& to a lesser extent, some are carnivores) adaptable to a wide variety of habitat and food bases. A turtle that can survive by skimming pond scum ought to be able to scrape by on what you feedJ!


Appendix I: Useful Web Links.

I.) Commercial Foods:

·        Tetra’s ReptoMin Page:

·        Mazuri’s Freshwater Turtle Food:


II.) Frozen Foods:

·        San Francisco Bay Brand: Gives a decent discussion of how they manufacture their products; shows some good thought.


III.) Thiaminase:

·        Table of fishes known to contain thiaminase (This article was originally shown to us on the Kingsnake Turtle Forum by Bill Moss).


IV.) Plant Matters:

·        List of Edible & Poisonous Plants: (several links; look lower on the page!).

·        USDA's Searchable Nutrient Database (Tell it a plant, get the nutrient breakdown; very nice site!!!).

·        Baby Tortoise Dietary Discussion & a nutrition table for plants:



V.) Miscellaneous Matters:

·        Freeze Drying Explained:

·        Robyn’s Snail Species Page:


VI.) Other Diet Discussions:

·        What Should I Feed My Turtle? By Mary Hopson

·        Austin’s Turtle Page:

·        Baby Tortoise Dietary Discussion & a nutrition table for plants:



VII.)         Tortoise Trust Website:



Appendix II: Wild Turtle Diet Examples:


1.)    Slider: Opportunistic omnivores with a wide variety of habitats. Initially predominantly carnivorous but progressively herbivorous with age.  Turtles of the United States and Canada cites research showing they start out strongly carnivorous & it continues into the second year but drops during the first year of growth; it’s thought the juvenile diet is calcium-rich & may aid shell-hardening; I’ve heard it suggested high-protein = fast growth & increased resistance to predation based on size. The percent animal material in the gut (dry weight) drops to between 0 & 10% at a plastron length around 4 – 6 cm (Clark, D.B.,, and J.W. Gibbons, 1969. Dietary shift in the turtle Pseudemys scripta (Schoepff) from youth to maturity. Copeia 1969: 704-706). Louisiana juveniles start out largely eating insects (mostly hemipterans and dragonfly nymphs) but gradually shift to plants (Hart, D.R. 1983. Dietary and habitat shift with size of red-eared turtles (Pseudemys scripta) in a southern Louisiana population. Herpetologica 39:285-290), paralleling a move from foraging in shallow to deeper water. However, adults still prefer animal material when available (Clark and Gibbons, 1969; Parmenter, R.R., and H.W. Avery. 1990. The feeding ecology of the slider turtle. In Gibbons, J.W., ed. Life history and ecology of the slider turtle, 257-266. Smithsonian Institution Press, Washington, D.C.).

2.)    Painted: Like sliders, an opportunistic omnivore with wide habitat variety that is initially carnivorous but progressively more herbivorous as it matures (Turtles of the United States and Canada, page 293). A study of 56 adults in Pennsylvania showed animal matter in 65% of stomachs (61.2% by volume) and plant remains in 100% (38.8% by volume) (Ernst, C.H.: I’m uncertain of the exact reference, but cited on Turtles of the United States and Canada page 293.) Basically, algae, vascular plants, and almost any organism large enough to see & small enough to kill & tear apart is fair game. Belkin & Gans (Belkin, D.A. and C. Gans. 1968. An unusual chelonian feeding niche. Ecology 49:768-769) described a surface skimming feeding they called neustophagia; evidently painted turtles can stick the head partly out of the water, open the mouth, expand the pharynx, and thus suck in surface film fine particulate matter. A turtle that can eat surface film. Unbelievable!

Note that the Ernst study indicates a higher percentage of animal matter in painted stomachs than RES in the Clark and Gibbons study. I don’t have the specifics of the studies, and as stated they aren’t exactly a direct comparison (were all 56 painteds adults? What about fully adult RES?). But tentatively it looks like painteds are more carnivorous than RES. My Southern Painted likes to graze on Anacharis, & eats Romaine lettuce when fresh.

3.)    River Cooter (there are subspeces): Turtles of the United States and Canada Page 329 states they’re mostly plant eaters, but maybe less so than other cooters & all ages may consume animal foods. Research was listed to back up the contention that they do eat considerable meat (for some reason, the Hieroglyphic river cooter was most cited on this).

4.)    Other Cooters: Turtles of the United States and Canada’s articles I browsed gave the impression they’re largely herbivorous as adults, but at least some species eat a variety of meat-based foods at least as juveniles. There is one noteworthy exception; Page 357 notes that Strecker (Strecker, J.K. 1927. Observations on the food habits of Texas amphibians and reptiles. Copeia (162): 6-9) found only mollusks (Sphaerium, Planorbis, Lymnaea) in digestive tracts of the Texas River Cooter and that Vermersch (Vermersch, T.G. 1992. Lizards and turtles of south-central Texas. Eakin Press, Austin, Texas. 170 pp.) reported the young actively pursued aquatic & terrestrial insects, crayfish, snails & other invertebrates when offered. My Question would be: how many turtles was the Strecker report based on?  This chapter is short relative to many; just under 2 ½ pages. People keeping Texas cooters may want to try to get copies of the studies cited (inter-library loan programs at colleges can be useful for this).

5.)    Map Turtles: A review of Turtles of the United States and Canada & the research cited within shows considerable variability of intake; for some species mollusks and insects are the prime players. I recommend map turtle aficionados get the book.

6.)    Stinkpot: Turtles of the United States and Canada (pages 147-148) noted those under 5 cm carapace length feed mostly on small aquatic insects, algae & carrion, and those over 5 cm on any kind of food. Newman (Newman, H.H. 1906. The habits of certain tortoises. J. Comp. Neurol. Psychol. 16:126-152) observed stinkpots on land grabbing slugs at dusk. In an Oklahoma study, Mahmoud (Mahmoud, I.Y. 1967. 1968b. Feeding behavior in kinosternid turtles. Herpetologica 24:300-305) found the following percentages by 1.) Frequency – 98.3% Insecta, 61.1% Crustacea, 96.1% Mollusca, 5.2% Amphibia, 37.4% carrion and 97.4% aquatic vegetation, and 2.) Volume – 46.4% Insecta, 5.0% Crustacea, 23.7% Mollusca, 1.1% Amphibia, 3.4% carrion and 20.4% aquatic vegetation. So arthropods and mollusks are #1, with aquatic plants still making a significant showing. In Florida, Bancroft et al. (Bancroft, G.T., J.S. Godley, D.T. Gross, N.N. Rojas, D.A. Sutphen and R.W. McDiarmid. 1983. Large-scale operations management test of use of the white amur for control of problem aquatic plants. The herpetofauna of Lake Conway: Species accounts. Misc. Pap. A-83-5. Army Engineer Waterways Exp. Stat., Vicksburg, Mississippi. 354 pp.) found that 99% of the plant biomass in stinkpot stomachs was Nuphar (56%), Vallisneria (26%), filamentous algae (9%) and Eichhornia (8%). Note: Nuphar luteam is the cow lilly (I’m unsure if that’s one they ate, but it’s found in Florida), Vallisneria a genera with representatives in the pet trade and Eichhornia crassipes is water hyacinth (I’m uncertain that’s the species they ate).

7.)    Eastern Mud Turtle: Turtles of the United States and Canada page 175 notes Mahmoud ((Mahmoud, I.Y. 1967. 1968b. Feeding behavior in kinosternid turtles. Herpetologica 24:300-305)) reported 1.) Frequency – 98.3% Insecta, 15.0% Crustacea, 93.1% Mollusca, 30.0% Amphibia, 68.6% carrion and 89.6% aquatic vegetation, and 2.) Volume – 30.4% Insecta, 1.4% Crustacea, 31.8% Mollusca, 2.2% Amphibia, 11.9% carrion and 22.3% aquatic vegetation. Note how similar to the stinkpot’s contents! Phil. Peak in Louisville advised me in his experience mud turtles are more terrestrial than commonly viewed (semi-aquatic rather than almost strictly aquatic, like stinkpots). Turtles of the United States and Canada page 171 notes the eastern is quite terrestrial with most land activity in morning or evening. Therefore it stands to reason their diet may differ slightly from stinkpots.’ On page 176 it’s noted by the author they’ve seen easterns eating on land on 2 occasions in northern Virginia.

8.)    Spiny Softshell: Largely carnivorous. Turtles of the United States and Canada page 122 cites research showing a lot of insect intake. A study of Iowa softshells showed a diet about 25% insects, 36.5% fish (likely carrion), 5.8% small fish (likely caught) & 55% crayfish (Williams, T.A. and J.L. Christiansen. 1981. The niches of two sympatric softshell turtles, Tionyx muticus and Trionyx spiniferus, in Iowa. J. Herpetol. 15:303-308). Plant material was found in 61% of the turtles’ stomachs. The percentage of varied foods by volume included 24.2% crayfish, 17.2% large fish, 2.2% small fish, 12.8% plant material, 6.7% Ephemeroptera, 1.9% Hemiptera, 0.6% Diptera, 3.0% Coleoptera, 19.5% unidentified animal material, 6.5% unidentified insect material, 2.0% sand &/or gravel, and minor percentages of other things. Evidently softshells will take advantage of what’s available, but mainly animal-based foods.


      For an excellent natural dietary reference, get a copy of Turtles of the United States and Canada. There are many turtles I chose not to cover, at least at this point (snappers, map turtles, box turtles, etc…).


Appendix III: References:

            If you have turtles, these first 2 books belong on your bookshelf. Period. If you have a general interest in unusual pets and enjoy some addition nutritional information, the 3’rd’s worth your money. I’ve linked these books to places you can buy them.

            a.) Turtles of the United States and Canada (Hardcover)

Turtles of the United States and Canada (Softcover)

            Outstanding book depicting the natural history of our native turtles. Divided into section by species, with sections broken down into Recognition, Karyotype, Fossil Record, Distribution, Geographic Variation, Confusing Species, Habitat, Behavior, Reproduction, Growth & Longevity, Food Habits, Predators & Defense, Populations, and Remarks. It surveys the 56 species of the U.S. & Canada. 

            Includes research study information on such matters as stomach contents, how long the turtle can survive underwater, chromosome number, homing ability if removed from original site and activity cycle by time of day and year. If you want to ‘know’ your turtle from his wild origins, this is the book.           

b.) Practical Encyclopedia of Keeping and Breeding Tortoises and Freshwater Turtles (Softcover) by A. C. Highfield.

            The title is definitive. If you want an ‘owners guide’ to turtles, buy it. Highfield speaks from extensive husbandry experience with a large variety of both tortoises and turtles. His section on nutrition includes a breakdown by nutrient of symptoms of deficiency & how to prevent it. Many color photo.s of disease conditions. Many species profiles giving an overall synopsis and often such tidbits as incubation info. and what incubation temp.s produce males or females. Both native and exotic turtles are discussed. If you only buy one of my recommended references, make it this one. 

c.) Encyclopaedia of Terrarium, by Eugene Bruins

(View and Buy at:

                        General terrarium guide discussing many animals including varied reptiles, tarantulas, scorpions, preying mantids, walking sticks and even grasshoppers. Although not turtle-specific, it has useful information in a smooth read format (witness how often I cited it in this article).