(Original Article by Richard Lunsford, with editorial & technical assistance from Phil Peak (a.k.a. Phil. in Louisville), forum regular specializing in mud & musk turtles, & Tom Coy of Austin’s Turtle Page, whose experience includes exotics.)

             The serious turtle-keeping hobby grows steadily. Thanks to the evolution of dedicated turtle-keeping forums on the World Wide Web, masses of enthusiasts gather to exchange information & experiences in a way unimaginable before 1995. Two of the greatest advances in popular knowledge I’ve seen are these:

1.)    Turtles should have large enclosures, whether a 125 gallon glass aquarium, a $15 Rubbermade container from Wal-mart or a plastic swimming pool made for kids. An adult red-eared slider should NOT be kept in a small tub! Example recommendations:

a.)    Adult male RES – at least a 55 gallon long, preferably a 75 gallon or larger. (I originally mentioned a 30 gallon long but Phil. felt a 55 gallon is too small for even a single adult RES, and Tom agreed & said “A 55 gallon is 48" x 12" x 20". Much better in all aspects, but I personally would not feel comfy putting an adult male in one solely for the fact that that leaves it only 3" (probably 1/2" less on the inside dimension) to turn around. It would have to tuck its head and tail in to turn around each time. I'd say a 75 for an adult male. A 75 has the same measurements for the most part, but it is 18" instead of 12" from front to back”).

b.)    Pair of male RES or 1 male & 1 female – at least a 75 gallon, and preferably a 125 gallon. With the 125, you could fit in a couple of mud/musk and maybe a pair of male map turtles, if water quality is very high.

c.)    1 or 2 Mud/Musk – at least a 20 gallon long, and preferably larger. (Phil. said musk turtles are more active & aquatic than mud turtles; he feels a 20 long is good for a pair of muds & a bit small for musk. He’s noted they avoid open spaces & seek the shelter/security of closed places. Phil.’s been redesigning his mud turtle setups with more land, which he said they fully utilize).

d.)    300 Gallon stock tanks are popular with several turtle, large turtle (alligator snapper, female softshell) or elaborate setups (Phil. reminded me since he has success with stock tanks).

e.)    Turtles deserve strong filtration – their water should be free of ammonia and nitrite build-up; water that just looks clear isn’t good enough. But turtle tanks should not be murky or have a prominent stench.

So, now that more & more people are spending several hundred dollars, and often over $1,000, on setups for turtles, it’s no wonder many watch 1 or 2 turtles swimming around that expensive setup and ask, “What else can I have?”

            Up till now, our answer has often been ‘nothing,’ ‘a second turtle,’ or ‘buy a Plecostomus and hope he doesn’t eat it.’ Bummer, huh?

             One problem is that of perspective; people tend to like ‘busy’ tanks with lots of variety, or diversity. Compared to natural aquatic environments, that translates to grossly overcrowded animals trapped in each others’ territory  & personal-space choking on high nitrate (the end-product breakdown product of their waste) concentrations IF their filtration system is even adequate and food isn’t allowed to rot in the tank.

Richard’s Laws of Successful Turtle Keeping:

 1.)    Thou shalt heavily over-filter.

2.)    LESS IS MORE!!! (Do NOT crowd the tank).

3.)    Thou shalt do at least a 50% water change every 2 weeks.

4.)    Thou shalt occasionally do water-testing & see that ammonia & nitrite stay close to zero and nitrate concentrations just before time for water changes aren’t too over-the-top. Do have at least a crude idea what your water’s pH is.

 Now, having said all that, if you’ve got a big, well-filtered system with extra room (or think you do), what can you keep with a turtle? The following is a compilation of sources; some things I’ve tried, some I’ve heard of from others who’ve tried them, and still others are logical to try.

 1.)    Other Similar Turtles –

a.)    You can generally mix most basking turtles (sliders, painted, cooters & maps). Caveats: Map turtles need very clean water. Some cooters get huge. Some turtles (RES, for example) can be territorial and aggressive. Sometimes a male will ‘fan’ (produce the penis) and another turtle will bite it; Someone on Kingsnake posted about a female RES attacking a male RES’s penis). Tom Coy had a male spiny softshell who thus injured a male Belize slider’s penis, which had to be surgically removed. Tom stated “Have also seen where other males have fanned and other turtles have indeed bit or tried to bite them.” If one of the turtles is wild-caught, it may have parasites (tape-worm, etc). Be sure everyone in the tank gets fed; not all turtles compete equally.

b.)    Mud & musk often mix fine, but may become territorial at least part of the year & have to be separated; Phil. posted about this, noting sometimes they have to be separated part of the year as this aggression can be seasonal, directed at rival males or unreceptive females of the same species. They can literally bite each others’ legs off (I read a post where one Florida mud did this to another). Phil. said mud/musk aggression can be brutal. I have to keep a young Mississippi mud turtle in a 75 gallon because the male stinkpot in my 200 gallon won’t tolerate it! (Note: stinkpots & Miss. muds look very similar). Phil. noted mud/musk usually mix with basking turtles just fine. 

c.)    Common and Alligator snappers should not be kept with anything else, including others of their own species. Further, they’re known to attack each other (common vs alligator snapper). Young may get along for awhile, but don’t plan on this being a permanent arrangement. I didn’t say it couldn’t be done, but it is NOT advised. I’d add the Big-Headed Turtle to this list, unless you want to breed them.

d.)    Softshells in indoor aquarium are vulnerable to fungal & bacterial infections, and being scratched by other turtles (even their own kind) isn’t desirable; do be careful here.

e.)    Tom C. had a small group of young Diamond Back Terrapins that for reasons unknown went at each other, resulting in deaths. Someone on a Kingsnake forum posted about a Diamond Back Terrapin possibly killing a RES (unless the RES died & the other munched on the corpse).

f.)      Do not mix turtles of greatly different sizes. (Note: the exception would be adult mud/musk with basking turtles, which are often much larger).Tom C. noted “…sometimes, depending on the species, the smaller turtle can be the aggressor. Recently I had to make some moves because a 2.5" Emydura subglobosa was beating up on a 6" and 5" snakeneck.” He said Eric B has found that they are extremely aggressive. (Emydura subglobosa = Red-Bellied Short Neck Turtle).

g.)    Tom C. noted “Placing unlike turtles is a bad idea. For the most part, placing any turtles together that are from different regions is never a good idea. Although I admit that I do try with cb only, I do my best to keep them separated by region.”

2.) Different Type Turtles -

a.)    Often a mud or musk turtle is added to a basking turtle tank; this usually works well, if you allow that the basker will out-compete the bottom-walker for most food by day & make sure everyone eats well. Make sure there are resting places so the bottom-walker (not as good a swimmer) can rest near the surface to breathe. One poster on Kingsnake claimed male mud/musk may drown baskers by trying to mount them; I’m under the impression this is rare. One person had an outdoor pond with a mud turtle that chased other turtles out of it.

b.)     Softshells are vulnerable to fungal & bacterial infections; their skin-covered shells, long narrow noses & (if they bury in substrate & extend their necks to breathe) their necks are vulnerable to bites. Conversely, individual softshells may be territorial and aggressive, and have powerful jaws. Have been kept in community turtle tanks, but emphasize lots of free swimming room, great filtration, frequent water changes & watch to see everyone gets along.

c.)    Side-necked Turtles – I have to wonder if those long necks might not intrigue a native U.S. turtle into nipping. You can try it.

d.)    Diamond Back Terrapins – Someone on Kingsnake posted about one found eating his tank-mate RES; it’s possible the RES died of natural causes, but that’s not the lead theory. Diamond Backs are kept in community tanks, so it’s probably a rare thing, but watch this species when mixing.

e.)    Specialty Species – At this point, people have enough problems working with Mata-matas, Chitra chitra and other oddball species; I don’t recommend the added stresses and variables inherent in community turtle tanks.

a.)    Fish – 

a.       Native U.S. Fish – One pet store employee told me they could get pumpkinseed perch (which he thought got 4 inches, but see below). You can dip-net these in many places. They), are large enough not to be eaten easily, lack long-flowing fins, and should be quick and agile. Recall that native U.S. fish are often cool-water fish (colder water has more oxygen), so tanks in the lower 70’s are a better match than those in the 80’s (although they may survive fine). Be warned: they are quick predators that’ll compete with your turtles for crickets, bloodworms, small snails, etc… Snappers can catch these.

Phil. has seen tapeworms coming out of the vent of sunfish. I saw this myself in one I kept in an aquarium. Whether that type of tapeworm can infect a turtle isn’t clear, but I DID have a common snapper get tapeworm (unclear if related). Try to either get captive-bred or at least the smallest wild-caught you can to reduce risk. Tapeworms generally aren’t fatal & do require intermediate hosts.

Phil. noted Pumpkinseed get OVER 4 inches; I searched the web and around 5-6 inches is typical, with 10 inches possible. Phil. also stated “If a person wants to keep sunfish with their turtles, I would advise against the more cold water species such as pumpkinseed, and opt for (IMO) the more beautiful and warm water tolerant long ear sunfish (Lepomis megalotis). Warmouth and green sunfish would also be good choices.”

Phil. added “As to the fish issue, I have a theory on this. If the turtles are accustomed to being around fish from a young age I think there is a better chance for long term cohabitation. I think that if one day someone introduces fish into their tank of half grown or adult turtles, they will most likely get eaten. I remember a number of years ago a neighborhood kid dropped by and gave me a bucket of fish he has caught in the creek. These were decent sized sunfish maybe 4"-6" long. Thinking they would be safe, I placed the still healthy group of fish in one of my 300 gal stock tanks that was housing adult RES and musk turtles. These turtles had never been exposed to fish in the past, and I was curious what their reaction would be. By morning each of these fish had been subdued and eaten, the only thing left being a couple of fish heads that they were still working on.”

b.      Tropical Perch Equivalents – The 2 obvious are Labidochromis caeruleus (electric yellow cichlids) from Africa (hard alkaline water) and Convict cichlids (from Central American s/w alkaline river environments). Yellows get 4 inches, are solidly built, intelligent and quick (what I said of Pumpkinseed applies except temperature) and are a loud yellow with black trim; very pretty (although your tank looks unnatural). Yellows can breed; trade young for feeders at the pet store. Convicts get around 6 inches, solid-built, pretty blue with black stripes motif, and one person on Kingsnake posted about success with these. Be warned: Convicts are VERY territorial when breeding & kill fish larger than themselves; they MIGHT be able to hurt a turtle, even one larger than they. You can try, but be careful.

Recommendation: don’t keep yellows or convicts in tanks under 55 gallons, and don’t keep over 2 yellows in a 55, 3 in a 75, or maybe up to 6 in a 125 gallon. For convicts, which I haven’t kept, I’d say only 2 in a 75 gallon, or MAYBE 4 in a 125. Convicts are large-bodied enough I don’t recommend in turtle tanks under 75 gallons.

Phil. advised avoiding Lab. caeruleus since they’re from hard, alkaline waters (& might be sensitive to nitrogenous wastes) & turtle keepers aim for somewhat acidic water (generally with higher nitrates). I’ve had Lab.s in fairly acidic water with somewhat elevated nitrate levels with no problems; your mileage may vary.

c.       Gold Fish – Can grow very large. Cold water fish so not optimized for tanks 78 – 82 degrees. Produce a lot of ammonia/waste. Long, flowing fins easily caught and ripped to shreds; not all that fast or maneuverable. Comets are faster without the big fins, but still get very large & produce a lot of extra waste. Not recommended.

d.      Guppies – feeder guppies evade turtles well but breed and your tank will swarm with them. May eat a little algae; good for eating stray bits of food. Kind of plain-Jane-looking. You can try fancy guppies; bigger flowing fins so maybe easier to catch. I don’t know if their babies will be fancy or not. A few fancy guppies may work, if you don’t mind killing half-grown young & feeding the bodies to your turtles.

e.       Plecostomus – eat algae & commonly kept with turtles. Comes in many varieties & some (like the Zebra Pleco.) don’t eat algae. The common pleco. can get huge at 18 inches in length; this is what most people have used. The Bristlenose pleco. gets 5-6 inches, is fairly large-bodied for its length, and is a great algae-eater although I’ve not heard of people keeping them with turtles. Clown pleco.s stay small at 3-4 inches, and are fair (but not great) algae eaters. Some people say get a pleco. larger than your turtle. Some have kept pleco.s successfully for years. Some have had turtles kill the pleco, eat the pleco, bite the pleco.’s eyes off, etc…a feeder until proven otherwise. Tom C. knows of one turtle who’s shell was bored into by a pleco.; rare, but if you have a large pleco. watch for this (Tom stated “It (the Pleco) was found latched on to the carapace of a young Mississippi Map. This turtle was kept by Kent who was in the process of experimenting with numerous types of pleco.s to keep with turtles,” and “I found a smaller one latched onto the face of a smaller turtle. The pleco. had been chewing the eyelids off. Obviously both were removed, but only one returned. The eyelids have grown back completely and there seem to have been no side affects from the ordeal. What is really odd, is that this is another E. subglobosa. Rather a dramatic difference between this passive specimen and the other, more aggressive one.”)

f.        Chinese Algae Eater – very common in stores. A fast, nervous little fish that evades turtles well & when young eats algae well. Reputedly doesn’t eat algae well as an adult & may attack other fish, esp. big slow ones, feeding off their slime coating & putting them at risk for infection. I have a pair and like them okay.

g.       Otocinclus – About 2 inch algae eaters from South America. Great algae eaters if you have several. Reputedly prone to die within days of purchase but most don’t & are hardy if they make it several days. They aren’t very wary around turtles and can be caught & killed. After a water change I saw one encrusted with many little bubbles; that slowed it & my painted killed & ate it. Walt G. on the forum tried 3 & they were eaten (RES & Diamondback Terrapin).

h.       Rosy Barb – Can reach 6 inches; said to only get about 3 inches in tanks. Males are a pretty red part of the time. They eat hair algae (the green stringy stuff) which is a plus. Fast, active, alert, entertaining to watch. I had one die (or be stunned) after a water change with cool water, & my painted ate it.

i.         Ropefish – look like 10 inch brown water snakes. Very timid & spend most of their time hidden inside synthetic hollow roots from the pet store; I have a pair, and my 3 turtles (stinkpot, Mississippi mud & S. painted, all young) get along with them. Need live or frozen food, so be ready to provide blood worms, brine shrimp, etc… They are escape artists so tanks with a few inches between the water & top, or covered with a screen, are recommended. Ideally kept in at least a pair. Don’t keep in tanks under 55 gallons. Could be injured by larger turtles (you could try with turtles that stay small, like mud, musk, Southern & midland painted, male map, spotted, etc…).

j.        Oscars – Big heavy cichlids from South America; fast-growing messy carnivores that churn out a lot of waste. Get something like 10-14 inches long. I saw a post from someone it works for, but another poster said one attacked his turtles (they can grab the legs, etc…). Will compete for turtle food. Fish enthusiasts on fish forums recommend keeping 1 Oscar alone in a 55 gallon tank, or 2 in a 75 gallon tank (as minimum sizes). Figure an Oscar & male RES are likely comparable in bioload on the tank. So don’t fool with Oscars in a turtle tank unless it’s at least 125 gallons & you’re willing to take the fish back to the pet store if trouble arises. Tom noted: “Oscars - Kent is currently running an experiment with them and turtles. He is currently housing a DBT with an oscar. This has been going on for a few months, and all seems well...so far. We'll have to wait and see how much time goes on before something happens, if anything at all. Neither one seem to be stressing the other out.”

k.      Big Aggressive Cichlids – Look, where do you think names like Red Devil, Green Terror, Jack Dempsey, Convict & Jaguar & Wolf Cichlid come from? I discussed convicts earlier, but unless you are VERY FAMILIAR with these others I do NOT recommend them.

l.         Powerful Fish – Electric catfish (yes, you can find them in the pet trade), fresh water moray eels and sting rays, red-bellied piranha…for crying out loud. NO!!!

m.     Catfish – remember that some catfish have sharp side-fins and thrash when grabbed; consider whether one could hurt your turtle. Stay away from big ones; compete with bottom walkers for food; can swallow some big things (don’t mix a big channel cat with hatchlings!!!).

b.)    Frogs, Newts & Salamanders –

People in Kingsnake’s Salamander & Newt forum made the case that amphibian species should not be mixed together. Amphibians produce toxins released through their skins. These vary in lethality by species, but may be toxic even to other species of amphibian. Therefore, the majority opinion is that pet amphibians should only be kept in species-specific tanks. So you don’t mix fire-bellied toads & Japanese fire-bellied newts.

Some newts are cool-water dependent & need temp.s not much warmer than 70 degrees. They can live 20 years & are not disposable pets.

Watching a turtle kill a frog is awful. The turtle grabs the soft amphibian in its hard, hooked beak, then rips at the helpless frog with it’s front claws, eventually ripping open & disemboweling the frog. Have some decency & don’t try keeping dwarf, African-clawed & other frogs with your turtles. Best-case scenario – frog dies horribly. Worst-case scenario – turtle dies from toxins.

c.)    Crayfish (Crawdads) – Can get about 6 inches, have large strong claws, & eat a variety of things. May clean up the tank a bit. Someone on Kingsnake posted about one killing his young softshell. Usually don’t injure turtles, and are often killed by them (common snappers seem adept at this). Could in theory cut a turtle or poke it in the eye with a claw in self-defense. I keep some young 3 inchers with my young turtles. Basically, don’t get attached & make sure the crawdad isn’t much bigger than the turtle.

Phil. from Louisville recently posted that he’s seen anchor worms & flukes attached to crawdads; I’m unclear whether anchor worms or whatever type of fluke he saw could infect a turtle. Do consider captive-bred (if practical) or starting out with very small ones & raising them (to minimize parasite exposure), and wash thoroughly before putting in the tank. Read under Ghost Shrimp (below) re: Beneckia chitinovora, as crayfish are also freshwater crustaceans and reportedly can carry this.

d.)    Ghost Shrimp – Transparent freshwater shrimp about 2 inches long. Cheap (about 5 for a dollar) & sold as feeders. Omnivores & clean up bits of crud in the tank; eat just a little algae. Lack the dangerous pinchers of crawdads. After you dump a bunch in the tank, turtles massacre many but several may survive for weeks in a big tank. The turtles will love these & they give hungry turtles the stimulation of hunting. Also, if you know food’s available if they work for it, you can better ignore begging turtles when it’s not a feed day.

Phil. from Louisville recently posted that he heard shrimp can carry a form of bacteria known as Beneckia chitinovora that’ve been linked to a form of shell rot.  Tom noted: “Agreed. Frye (1991) mentioned that they can harbor a variety of pathogens that can cause various problems, one of which is bacterial shell rot. Source for this being Reptile Medicine and Surgery by Dr. Mader.” Personally, I think if you look hard enough there’s something wrong with almost anything, and many people keep these without apparent ill effects, but I concur it’s worth mentioning and knowing about. If you have turtles with frequent or severe shell rot problems, ghost shrimp & crawdads may not be a good choice.

e.)    Snails – Many turtles (esp. mud & musk) love to eat these. Apple snails, Columbian Ramshorn snails, Mystery Snails, Pond snails…if too large to eat, may live in your tank, eat a little algae, clean up uneaten food, etc… Many snails are hermaphroditic but require a mate, so if you have one, you won’t see young unless it’s already ‘gotten busy’ at the pet store. You aren’t likely to have snail population explosions in a turtle tank. I breed Columbian Ramshorn snails for my mud and musk; even my S. painted eats small ones.

Snails can be an intermediate host for some parasites; someone once told me flukes, for example. Phil. recently posted “…I have heard of a study done on loggerhead musk turtles in which they determined that a large percentage of adults were suffering from lung fluke infestation that was caused from their diet in some areas being based primarily on a form of gastropod that served as an intermediate host.” Snails are a form of gastropod, by the way. From this we learn 3 things: 1.) Snails are a natural food of loggerhead musk turtles, who probably enjoy them a lot. 2.) Snails CAN carry parasites that can injure (perhaps even kill?) a turtle. 3.) Intermediate host means the snail has to get a parasite form produced by the end host (i.e.: turtle poop), then the fluke has to develop inside the snail, then get into a turtle. You don’t get snail-to-snail transmission. Snails that are produced in captivity in containers with no turtles present should not ever contract the parasite. You COULD infect snails by keeping in a tank with a turtle already infected. Bottom line: Use captive-bred snails from pet stores or friends’ tanks (if they don’t treat with chemicals!); don’t use wild-caught snails. And don’t breed your snails in containers with turtles from the wild who may harbor flukes and such. Phil. stated “The reference to lung fluke infestation in loggerheads was by Cox 1988.The snail type was Goniobasis, and the lung fluke was Heronimus mollis.”

f.)      Plants – Plant Aquarists recommend lighting levels of 2 to 3 watts/gallon, which means either compact fluorescent or metal halide light fixtures. A 3 foot compact fluorescent fixture with a 96 watt bulb (made by Compact Sea Life) called a Brite Lite generally costs around $130 online. You may better enjoy your turtles under strong lighting. Some plants (Java fern, Java moss, Anubias species) reputedly do okay in lower lighting. An old Kingsnake regular from way back named Ben once told me he thought he heard Java fern could be toxic; I quit using it when I thought my S. painted was biting at it. A.C. Highfield’s book Practical Encyclopedia of Keeping and Breeding Tortoises and Freshwater Turtles he mentions Java Fern as a viable option, so evidently it’s worked fine for some people. To use plants, you need substrate, too.

To learn more about lighting, go to www.thekrib.com ; it’s a wonderful resource to learn about lighting, substrate, planted tanks and algae.

Plants are viable in large tanks with a few smaller turtles. I keep a 200 gallon tanks; I’ve had luck with one Amazon sword plant, a couple of Aponogeton ulvaceous (like Wal-mart sells bulbs for), a couple of Aponogeton crispus (from PetsMart), a Cryptocoryne wendtii (red version – from PetsMart), Red Ludwigia (from PetsMart) and Anacharis (which omnivorous turtles like to graze on).