Venomous Snakes: Care and Habits of the Cottonmouth or Water Moccasin

Threat display

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Big and bold, the Cottonmouth or Water Moccasin is one of the most frequently-encountered of the USA’s venomous snakes. Stories of its alleged ferocity abound, and many folks living within its range are convinced that it goes out of its way to attack people. I’ve had the chance to work with this impressive serpent at the Bronx and Staten Island Zoos (Note: venomous snakes should never be kept in private collections), and to observe it in the wild, and have found its actual habits to be far more interesting than the supposed ones! From scavenging road-killed pigs to turning up in areas far north of where most people “expect” it, the Cottonmouth is full of surprises. Today I’ll focus on the natural history and captive care of the Eastern Cottonmouth (Agkistrodon piscivorous picivorous), with some comments on the 2 related subspecies.


Typical adult

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Most Eastern Cottonmouths are olive to dark brown in color, and are patterned with irregular, dark cross-bands. However, nearly-black, pattern-less individuals are common, and hybrids (which vary in appearance) occur where its range overlaps with that of the Florida and Western Cottonmouths.

They are stoutly built, and this makes adults appear larger than their actual size. Most average 3 to 5 feet in length, but occasional “giants” turn up. The published record length is 6 feet, 2 inches…but there’s no shortage of people who will claim to have seen, or even killed, Cottonmouths twice or three times as large (note – they haven’t!).


Green Watersnake

Uploaded to Wikipedia Commons by John Sullivan Cali

Several of the larger, non-venomous water snakes of the American Southeast are often confused with the Cottonmouth, as they are superficially similar in appearance and share the same habitat. And if you’ve ever tried catching a large Brown or Florida Green Watersnake, you’ll understand why most “non-herpers” give these irascible brutes as wide a berth as they do Cottonmouths!


The Cottonmouth is classified in the family Viperidae, and is most closely-related to the Copperheads and various Cantils of Mexico and Central America.



The Eastern Cottonmouth is found from southeastern Virginia to eastern Alabama and Georgia. I grew up associating Cottonmouths with Florida’s swamps and canals, and indeed it is there that the Florida Cottonmouth, (A. p. conanti) thrives in good numbers. I was surprised to learn, however, that the Western Cottonmouth(A. p. leucostoma)ranges much further north than I expected – to southern Illinois and eastern Missouri.


Typical Habitat

Uploaded to Wikipedia Commons by Moni3


Cottonmouths are typically found in and along slow-moving bodies of water such as swamps, marshes, canals, rice fields, ponds and weedy lakes. However, they will forage in fields, open woodlands and around farms, often far from water. Individuals in many populations hunt mainly by night, especially during the summer, but they bask in the daytime.


In the northern sections of their range, Cottonmouths hibernate in subterranean dens on land, often on hillsides far from water. Hibernation sites may be shared with copperheads, rattlesnakes, water snakes, ratsnakes and other species.



Cottonmouths can be quite common in suitable habitat and in protected areas such as the Everglades, but are threatened in some regions by wetland drainage. Basking Cottonmouths are said to be used for “target practice” in some places…not much of a challenge, given their size and immobility when basking, I imagine!



Zoo specimens have reached at least age 24; several under my care were in their late teens, and still full of spunk. Longevity in the wild has not been well-documented, as far as I know.



Uploaded to Wikipedia Commons by Accipiter


In most populations,females breed every-other-year, usually in August and September. The young, 1-16 in number, are born alive and are 7-13 inches in length. They are reddish-brown and vividly marked, and use their bright yellow tail tips to lure frogs, lizards, and other prey. Sexual maturity is reached in 3-4 years.



Cottonmouths take a wider range of prey than do most other snakes, and even scavenge road-kills. I was once very surprised to read a journal note (Herpetologica?) describing a large individual consuming chunks of fat from a dead pig!


The usual diet is extremely varied, and may include catfish, bream, eels and other fish, sirens, amphiumas and other salamanders, frogs, hatchling alligators, small turtles, lizards, snakes, ducks and other birds, and mammals such as rice rats, muskrats and voles.


I once housed a colony of Green Anoles with a pair of Cottonmouths at the Bronx Zoo. Whenever I tossed roaches or crickets in for the lizards, the Cottonmouths would move about in an apparent search for food. I’m wondering if youngsters consume insects as well; the closely-related Copperhead has been observed feeding upon cicadas and grasshoppers.


Cottonmouths under my care were fed minnows, shiners, trout, goldfish, mice and rats; I’ve always meant to try crayfish, but unfortunately did not. Like many fish-eating snakes, they seemed perpetually hungry. The opening of their exhibit door, with or without the scent of food, generally elicited a mad rush forward. All those I’ve kept adjusted well to captivity – thrusting them away with a snake hook did nothing to damper their desire to feed!


Light-colored individual

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Additional Information

The name “Cottonmouth” arose from this species’ threat display – when cornered, it throws back its head and gapes widely to expose the cottony-white interior of the mouth. If this fails to dissuade the intruder, the snake strikes repeatedly. Basking animals usually drop into the water and swim away, either below or at the surface, when disturbed.


Classification of Cottonmouths and other Vipers

Cottonmouths and their relatives, collectively known as “pit vipers”, are placed in the family Viperidae and subfamily Crotalinae, along with palm vipers, rattlesnakes, copperheads and related species. They are considered to be the most advanced, or highly evolved, of all snakes.


Crotalids, or pit-vipers, possess a sophisticated sensory organ (the “pit”) that detects the infra-red rays produced by birds and mammals. Located between the eye and nostril, this organ is far more sensitive than the heat receptors that have evolved among the boas and pythons. The arrangement of the heat receptors within the pit viper’s sensory organs are replicated in the brain and integrated with visual information received there. The pit may thus be considered more of an “imaging device” than mere heat receptor, and likely provides detailed information concerning the size and shape, as well as location, of warm-blooded animals. Aided by these unique organs, pit vipers are able to hunt and escape predators even in complete darkness.


Vipers possess long, hinged fangs that fold back against the roof of the mouth when not in use. Venom is injected with a single bite, in the manner of a hypodermic needle. The snake then retires and allows the prey to run off, and follows its scent trail once the stricken animal has expired. This strategy spares vipers the injuries that can be inflicted by prey animals upon snakes such as cobras, which must hold on while injecting venom. When attacking frogs, fish and other relatively benign prey, however, Cottonmouths hold onto the animal after striking.

Hi, my name is Frank Indiviglio. I’m a herpetologist, zoologist, and book author, recently retired from a career spent at several zoos, aquariums, and museums, including over 20 years with the Bronx Zoo.

Please check out my posts on Twitter and Facebook.   Each day, I highlight breaking research, conservation news and interesting stories concerning just about every type of animal imaginable. I look forward to hearing about your interests and experiences as well, and will use them in articles when possible.


Please also post your questions and comments below…I’ll be sure to respond quickly. Thanks, until next time, Frank.


Further Reading

The World’s Largest Rattlesnake

Keeping Watersnakes



Is a Red-Eared Slider a Good Pet? Read This Before Buying a Turtle

Sliders basking

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The Red-Eared Slider (Trachemys scripta elegans) is without question the world’s most commonly-kept pet turtle. But while these attractive reptiles are extremely responsive to people, many novice owners underestimate the amount of care and space their upkeep requires…and do not realize that Sliders commonly live to age 20+, and often well beyond. Over time, these factors lead many people to release or re-home their once beloved pets. As a consequence, Sliders have become established, in the wild, in dozens of US states and in countries ranging from Brazil to South Africa and Japan, where they are causing ecological havoc. Turtle adoption services and reptile rescues house literally thousands more unwanted pets. Please read this article carefully before buying or adopting a Red-Eared Slider, and be sure to post any questions below. Please also see the linked articles on the care of Sliders, Map Turtles and similar species.


Slider in outdoor pond

Uploaded to Wikipedia Commons by Lawrencekhoo

Aquarium Size and Upkeep

Female Sliders reach 8-12 inches in length. I personally measured one that was just over 12 inches long…and 11 ¾ inches wide! Males generally top out at 6 inches, but both sexes are very active, and will languish in cramped quarters. An adult female will require a 75-100 gallon aquarium, a commercial turtle tub, or a wading pool. Pairs rarely do well together, as the overly-amorous males constantly harass the objects of their desire with mating attempts.


Turtles are messy feeders and very hard on water quality. Powerful filters help, but even so partial or total water changes will be necessary. If a large plastic storage container is used as a home, it must be emptied and cleaned several times weekly.


Slider nesting

Uploaded to Wikipedia Commons by Nephets


With so many being up for adoption, Slider ownership might appear to be a good deal. But the initial purchase price of any reptile is generally the smallest of the related financial considerations. In addition to large and expensive aquariums and filters, Slider ownership entails electricity use, veterinary care, and the purchase of UVB bulbs and fixtures, heat bulbs and fixtures, water heaters, basking platforms, food, and mineral supplements.


Veterinary Care

Veterinarians willing to treat reptiles are difficult to find in many regions, although those experienced in turtle care are becoming more common. It is always a mistake to obtain a reptile of any kind before locating a veterinarian, or to imagine that even the hardy Slider will not require medical care at some point. Veterinary costs for reptiles are comparable to those charged for dog or cat care.


Hatchling slider

Uploaded to Wikipedia Commons by Jf268


Sliders routinely reach age 20 in captivity, and have the potential to live much longer. The published longevity record is 41 years, but I’m quite sure, judging from experience with related species, that there are some that have exceeded the half-century mark. That cute little hatchling you bought for your child may become your (much larger!) responsibility when she or he goes off to college.


Health Considerations

Salmonella bacteria, commonly present in turtle digestive tracts, can cause severe illness in people. Handling an animal will not cause an infection, as the bacteria must be ingested. Salmonella infections are easy to avoid via the use of proper hygiene, but are a serious concern for children and elderly or immune-compromised adults. Please speak with your family doctor and see the article linked below for further information.


Razorback Musk Turtle

Uploaded to Wikipedia Commons by Ltshears

Slider Alternatives

Several Map and Painted Turtle species share the Slider’s lifestyle, good nature and hardiness, but do not grow quite as large. Common Musk Turtles, Eastern Mud Turtles and a number of their relatives are even smaller, and do not need a source of UVB radiation. All make great pets, and become quite responsive to people. There are a great many other possibilities as well…please see the linked articles and post below for further information.


Please check out my posts on Twitter and Facebook. Each day, I highlight breaking research, conservation news and interesting stories concerning just about every type of animal imaginable. I look forward to hearing about your interests and experiences as well, and will use them in articles when possible.


Please also post your questions and comments below…I’ll be sure to respond quickly. Thanks, until next time, Frank Indiviglio.


Further Reading

Common Musk Turtles in Captivity: the Perfect Pet Turtle

Slider, Map and Painted Turtle Care




I Found an Orange Salamander: Is it a Red Eft and Does it Make a Good Pet?

Red Eft

Uploaded to Wikipedia Commons by Bruce Lucas

As the summer weather cools and kids return home from camp, questions concerning Red Eft care are among the most frequent I receive. Bold, brightly-colored, and often out by day, Red Efts are more commonly-collected by children than any other amphibian. And, being attractive and seemingly-benign, they are also less likely to be rejected outright by parents. However, efts are temperature sensitive and require a specialized diet. Unfortunately, they are poorly-suited to captivity, especially when inexperienced owners are involved. In the following article I’ll explain why, and will offer some alternative species and care tips to folks intent on trying to keep these beautiful salamanders.


Natural History: What is an Eft?

The term “Eft” refers to a temporary land stage in the life cycle of the Eastern Newt (Notophthalmus viridescens). This species’ huge range extends from southern Canada through most of the central and eastern USA to Texas and Florida; in North America, only the Tiger Salamander has a wider distribution. Four subspecies have been described.


Eastern Newt (Eft's Adult Phase)

Uploaded to Wikipedia Commons by Raeky

The olive-green, red-spotted adult newts are aquatic, and at one time were a pet trade mainstay. Many states now prohibit collection, but where ownership is legal they make wonderful introductions to amphibian care (please see the article below).


In most populations, Eastern Newt larvae transform into orange to red-colored efts. The efts leave the natal pond and take-up residence in forested areas. The eft stage generally lasts from 2-3 years, but may extend to 7 years in the northern part of the range and in mountainous habitats. The eft stage is skipped in certain populations, with the larvae developing directly into aquatic adults. “Eft-skipping” was first documented on Long Island, NY, but has since been found among all subspecies, and across the range. It most often occurs where the land surrounding breeding ponds is sandy or otherwise inhospitable to moisture-loving amphibians.


Skin Toxins

Efts are well-protected by powerful skin toxins. This seems to account for their tendency to wander about on damp days, seemingly oblivious to the attentions of curious children (always wash after handling one, as their skin secretions can irritate mucus membranes, eyes and wounds). Several other species, including the Mud Salamander (Pseudotriton montanus) and the Red Salamander (P. ruber), are believed to mimic the Red Eft in order to discourage predators.



Uploaded to Wikipedia Commons by Tpe

Captive Diet

Wild-caught efts are not at all shy, and willingly forge by day. Judging by the questions I receive, however, it seems that many Red Eft owners are first-time salamander keepers, and are not prepared for the work involved in keeping these gaudy little gems. By the time most folks write in, their once-perky little pets are lethargic and emaciated.


Red Efts require a highly-varied diet comprised of tiny invertebrates, and will not accept the dry foods and pellets favored by adult newts. Those experienced in keeping Dart Poison Frogs and other small amphibians usually have no trouble with efts, as a number of frog foods suit them well. Flightless fruit flies, 10-day old crickets, springtails, bean beetle larvae and sow bugs can be purchased from online dealers, and are readily accepted. In order to add variety to the diet, termites, millipedes, tiny earthworms, beetles and other small leaf-litter invertebrates should also be collected when possible (please see the article linked below).


Heat Sensitivity

While different eft population vary in regard to temperature requirements, most fare poorly when kept at 72 F or warmer for any length of time. A cool basement or similar location is essential to their survival.


Look But Don’t Touch

Children are drawn to efts because they accept handling without protest. However, it’s important to realize that handling damages the skin’s protective mucus covering, leaving the animal exposed to attack by bacteria and other pathogens. As mentioned above, skin secretions can also irritate people. Furthermore, all amphibians can be assumed to harbor Salmonella bacteria. While infections are easily preventable if proper hygiene is maintained, children must be supervised carefully.


Fire Salamanders

Uploaded to Wikipedia Commons by Überraschungsbilder

Eft Alternatives


Those seeking a land-dweller cannot do better than the Fire Salamander. These gorgeous creatures, captive bred in large numbers, are among the most responsive of all amphibians…and, with proper care, they may live to age 30, 40, or beyond! Please see the article linked below.


A wide array of semi-aquatic species, including Fire-Bellied, Paddle-Tailed and Ribbed Newts, are being bred in captivity and make hardy, long-lived pets. As mentioned earlier, the Red Eft’s adult phase is also a good choice, but captive-bred specimens are scarce. Please see the linked articles and post your comments below if you’d like more details on newt and salamander care.

Hi, my name is Frank Indiviglio. I’m a herpetologist, zoologist, and book author, recently retired from a career spent at several zoos, aquariums, and museums, including over 20 years with the Bronx Zoo.

Please check out my posts on Twitter and Facebook.   Each day, I highlight breaking research, conservation news and interesting stories concerning just about every type of animal imaginable. I look forward to hearing about your interests and experiences as well, and will use them in articles when possible.


Please also post your questions and comments below…I’ll be sure to respond quickly. Thanks, until next time, Frank.


Further Reading

Eastern Newt Care


Collecting Leaf Litter Invertebrates


Fire Salamander Care

Pet Lizards: Large, Small, and Colorful Insectivores

Rainbow Whiptail

Uploaded to Wikipedia Commons by DiverDave

The world’s astonishing lizard diversity – 5988 species have been described to date – is mirrored by the huge array of species now available to reptile enthusiasts. In recent years, refined husbandry and breeding techniques have introduced and re-introduced many fascinating lizards to the pet trade. Today I’d like to cover several that might interest folks with varying degrees of experience. I’ll review others in the future…until then, please post notes about your own favorites below, as those mentioned here are just a small sample.


Important Notes

A highly-varied diet is essential if you are to have success in keeping insectivorous lizards. Crickets and mealworms alone, even if powdered with supplements, are not an adequate diet for any species.


Always provide your lizards with the largest possible enclosure. Large terrariums will simplify the establishment of a thermal gradient (areas of different temperatures). Thermal gradients, critical to good health, allow lizards to regulate their body temperature by moving between hot and cooler areas.


Few diurnal (day-active) lizards will thrive without a source of UVB light.  If a florescent bulb is used (the Zoo Med 10.0 UVB Bulb is ideal), be sure that your pet can bask within 6-12 inches of it. Mercury vapor bulbs broadcast UVB over greater distances, and provide beneficial UVA radiation as well.


The following information is meant to provide an overview. Please post below for more detailed information.


Emerald Swift

Uploaded to Wikipedia Commons by Charlesjsharp

Emerald Swift, Sceloporus malachiticus

Also known as the Green Spiny Lizard, mature males are breathtaking even by lizard standards. Note the Latin species name – malachite green, with a blue tint, best describes these beauties. Although many in the trade are wild-caught, captive births (they bear live young) are becoming more common. Emerald Swifts range from southern Mexico (Yucatan) through Central America to Panama, and are restricted to cloud forests and similar mountainous habitats.


Unfortunately, as with most habitat specialists, care can be somewhat complicated. Emerald Swift terrariums must be kept rather cool and humid (74-76 F, humidity 60-70%), but hot, dry areas (90 F) must also be available. As airflow is important to their health, the screen top should not be covered with plastic as a means of increasing humidity; rather, a reptile fogger, or frequent hand-misting, should be employed.


A pair might get by in a 30 gallon terrarium, but a 55 gallon, which will also support a second female, is preferable. Driftwood and rocks should be supplied for climbing and basking; all rocks should be placed on the tank’s floor, not on the substrate, so that tunneling lizards will not be crushed. UVB exposure is essential. A highly-varied diet comprised of well-fed, calcium and vitamin-supplemented roaches, crickets, butterworms, waxworms, calciworms, silkworms, hornworms and wild caught insects is critical for their long-term health. Like most related lizards, Emerald Swifts are high-strung and should be viewed as pets to observe rather than handle.


Long tailed Grass Lizard

Uploaded to Wikipedia Commons by B kimmel

Long Tailed Grass Lizard, Takydromus sexlineatus

This active, attractive lizard is also sold as the Asian Grass or Six Lined Grass Lizard. Originally available only as wild-caught imports, they have proven to be prolific breeders, with multiple clutches per year being common. Their huge natural range extends from India and China through most of Southeast Asia to Indonesia. Long toes and an extraordinarily-long tail (an individual with a 2.5 inch long body will sport an 8 inch tail!) enable these little acrobats to hunt in the “canopy” of their grassland home – a niche unavailable to other lizards.


Although small, Grass Lizards are very active. A trio should be provided a 20 long to 30 gallon terrarium. If given sufficient space and cover, a small group can be maintained together; success has also been reported in housing them with small geckos, treefrogs and anoles. The terrarium should be well-stocked with real and artificial plants and branches, as they are stressed in bare enclosures.   UVB exposure is essential, and a temperature gradient of 72-85 F, with a basking site of 90-95 F, should be established.  A diet comprised of as many insect species as possible must be supplied; crickets and mealworms alone are not adequate.


Sudan Plated Lizard

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Sudan Plated Lizard, Gerrhosaurus (Broadleysaurus) major

This thickly-built lizard appears quite formidable, but it is actually calm in demeanor, and usually becomes a most responsive pet. Also a long-lived pet – a pair under my care at the Bronx Zoo was still actively-courting at age 25+. The “Sudan” part of this lizard’s name is misleading, for its enormous range extends from that country clear across the width of Africa, and south along the continent’s western coast to South Africa. “Plated” is, however, apt, as they sport very sturdy, thick scales. Sudan Plated Lizards favor semi-arid scrub, brushy savannas and lightly-wooded grasslands, and may also colonize parks and other developed areas.


Plated Lizards really come into their own in large enclosures, and should not be considered unless a cage of at least 4’ x 3’ x 3’ (and preferably larger) is available. Those I’ve kept in large zoo exhibits were doing something interesting all day long…the same cannot be said for the many poorly-housed specimens I’ve seen over the years. They prefer to bask on rocks, and are inveterate diggers. Be sure to place all rocks on the terrarium’s floor, not on the substrate, or a lizard may tunnel beneath one and be crushed. A deep layer of sand and gravel should cover the cage bottom; PVC tubes and similar shelters make great retreats. Plated Lizards do well at a temperature gradient of 76-88 F and with a basking site of 95F. Ample UVB exposure is essential.


Providing a varied diet to these ever-hungry lizards is a simple matter, as little will be refused. Mine relished the cicadas, crayfish and may beetles, along with all of the standard feeder insects. Interestingly, they also take earthworms, which are rejected by most arid-adapted lizards. An occasional pink mouse can be offered, but rely primarily upon supplements rather than vertebrates as a calcium source (wild individuals do take the occasional small lizard or snake, but they are mainly insectivorous). Fruit is accepted by many individuals, but they seem to do fine without it.


Hi, my name is Frank Indiviglio. I’m a herpetologist, zoologist, and book author, recently retired from a career spent at several zoos, aquariums, and museums, including over 20 years with the Bronx Zoo.

Please check out my posts on Twitter and Facebook.   Each day, I highlight breaking research, conservation news and interesting stories concerning just about every type of animal imaginable. I look forward to hearing about your interests and experiences as well, and will use them in articles when possible.


Please also post your questions and comments below…I’ll be sure to respond quickly. Thanks, until next time, Frank.


Further Reading

The Best Diets for Insect-Eating Lizards


How to Breed Swifts and Spiny Lizards

Diamondback Terrapin Care: Keeping the USA’s Most Unique Turtle

Diamndback terrapin

Uploaded to Wikipedia Commons by Tom

The Diamondback Terrapin (Malaclemys terrapin) is often described as the most beautiful turtle in the Western Hemisphere, if not the world. It is also distinguished by being the only turtle adapted to life in estuaries, salt marshes and other brackish habitats (water that is neither fresh nor marine). Long considered a delicate pet, the needs of this spectacular animal are now well-understood, and captive-bred specimens are increasingly available. My first Diamondback, received in childhood, was a hatchling. That ill-fated creature was quickly consumed by a Blue-Claw Crab (long story!), but later experiences with this species in the wild, at home and in zoos has (hopefully!) enlightened me as to their proper care. We still have much to learn, however, so please post your own observations below.



The Diamondback Terrapin varies greatly throughout its range, but is always breathtaking. The carapace, marked with deep concentric grooves and ridges, is unique in the turtle world. Other shell markings vary, with the most eye-catching being born by the aptly-named Ornate Diamondback (M. t. macrospilota) of Florida. The skin is also unusually-attractive, ranging from pearl-gray to black in color, and decorated with dark flecks and slashes. Males average 5-6 inches in length, while females may approach 10 inches.


Range and Habitat

Although the Diamondback Terrapin is a habitat specialist, its range is among the largest of any US turtle. Seven subspecies are found along the Eastern and Gulf coasts of the USA, from Cape Cod, Massachusetts through the Florida Keys and along most of Texas’ eastern coast (to the vicinity of Corpus Christi). An isolated population lives along Bermuda’s coastline.


Diamondbacks are found only in those habitats that straddle the line between fresh and salt water – coastal salt marshes, estuaries, tidal flats near river mouths and protected lagoons. Highly aquatic, they often bask by floating at the water’s surface. Some populations also spend varying amounts of time in purely-marine water.


Tidal creek

Uploaded to Wikipedia Commons by Captain-tucker

Tidal creeks spanned by footbridges are great places to observe wild Diamondbacks. If unmolested, they will forage and bask without regard for prying eyes. I know of several sites on Long Island, NY where, due to the height of the footbridges, I can sometimes see terrapins picking snails and other invertebrates from bridge pilings.


Populations have been decimated by collection for the food trade and habitat loss, and many perish as “by-catch” in commercial crab traps. These unique turtles are protected throughout their range, but regulated commercial harvesting is permitted.


The Terrapin Aquarium

Even by aquatic turtle standards, Diamondback Terrapins are extremely active. While a 75 gallon aquarium might suit a male, females need tanks of at least 100 gallon capacity, commercial turtle tubs or ponds.


A dry basking surface is essential. Commercial turtle docks and ramps suffice for smaller specimens, but adults will likely sink anything that is not affixed to the glass with silicone adhesive. Cork bark wedged between the aquarium’s sides is another option.



Uploaded to Wikipedia Commons by Flickr upload bot

Salinity of the Water

While individuals from some populations have adapted to fresh water in captivity, keeping them so is not recommended. Fungal and bacterial skin infections are commonly seen when Diamondbacks are denied access to salt water, and internal ailments may develop as well.


Marine salt marketed for aquarium fish should be used to raise salinity to 1.014-1.018. Water evaporation will cause the salinity to increase (salt does not evaporate), so be sure to take weekly readings with an aquarium hydrometer. 


Diamondback Terrapins remove some salt from the water they ingest, but should also be placed in fresh water 1-2 x weekly and allowed to drink for 10-20 minutes. Some keepers do fine with less-frequent fresh water immersion, and by using rock salt instead of aquarium salt, but I prefer to err on the side of caution.



Water quality is extremely important…more so than for most other turtles. Fouled water invariably leads to skin infections. As Diamondbacks are adapted to the alkaline water habitats, it is advisable to check your aquarium’s pH regularly with a simple test kit or pH strip. Turtle wastes and uneaten food will cause the water to become acidic, which will leave your pets open to attack by various fungi and bacteria.


Turtles are messy feeders and very hard on water quality. Unless the enclosure can be emptied and cleaned several times weekly, a powerful submersible turtle filter or canister filter will be necessary. Even with filtration, partial water changes are essential. Please see the articles under “Further Reading” for more on filtration, and links to useful models.


mediaRemoving your turtles to an easily-cleaned container for feeding will lessen the filter’s workload and help to keep the water clean; please see the article linked below.



Diamondback Terrapins are best kept in bare-bottomed aquariums. Gravel traps wastes, which greatly complicates cleaning.



A source of UVB radiation is essential. If a florescent bulb is used (the Zoo Med 10.0 UVB Bulb is ideal), be sure that the turtle can bask within 6-12 inches of it. Mercury vapor bulbs broadcast UVB over greater distances, and also provide beneficial UVA radiation.



Water temperatures of 70 – 76 F should be maintained. These large, robust brutes often break typical aquarium heaters, so choose a “turtle-proof” model. An incandescent bulb may be employed to heat the basking site to 85-90 F.


Green Crab

Uploaded to Wikipedia Commons by Lmbuga


The Diamondback Terrapin’s broad, crushing jaw surfaces are an adaptation to a diet comprised largely of hard-shelled crustaceans and mollusks such as crabs, snails, clams, mussels, barnacles and shrimp; fish, marine worms and algae (seaweed) are also taken. Pets should be offered a diet based upon whole marine animals such smelts, shiners and other bait fish, prawn, crabs (i.e. bait crabs), squid, conch, periwinkles (available in many seafood stores) and similar foods. I occasionally use bags of mixed “chowder” seafood as a means of adding variety to the diet.


Collecting Diamondback Terrapin food brings one into contact with countless fascinating creatures, so I try to gather or trap snails, mussels, clams, spider crabs and fishes for my charges whenever possible.


Most individuals will also accept commercial turtle pellets and trout chow, which can comprise 40-50% of the diet. I favor Zoo Med’s products and Reptomin.


Without sufficient exercise, your terrapin’s jaws will quickly become over-grown. Shells, exoskeletons and bones also supply calcium, which is needed in great quantities by this dietary specialist. A cuttlebone or turtle mineral block should be available as a calcium supplement and to supply beak-trimming exercise.



Gravid (egg-bearing) females usually become restless and may refuse food. They should be removed to a large container (i.e. 5x the length and width of the turtle) provisioned with 6-8 inches of slightly moist soil and sand. Gravid females that do not nest should be seen by a veterinarian as egg retention invariably leads to a fatal infection (egg peritonitis). It is important to note that females may develop eggs even if un-mated, and that pets may produce several clutches each year.


The 4-20 eggs may be incubated in moist vermiculite at 80-82 F for 55-65 days.



Diamondback Terrapins make very responsive pets. Most feed readily from the hand, and adapt well to busy households. However, all turtles are capable of administering powerful bites and scratches when frightened, and must be handled with care…this is especially true of a large species that can crush snail and clam shells!

Hi, my name is Frank Indiviglio. I’m a herpetologist, zoologist, and book author, recently retired from a career spent at several zoos, aquariums, and museums, including over 20 years with the Bronx Zoo.

Please check out my posts on Twitter and Facebook.   Each day, I highlight breaking research, conservation news and interesting stories concerning just about every type of animal imaginable. I look forward to hearing about your interests and experiences as well, and will use them in articles when possible.


Please also post your questions and comments below…I’ll be sure to respond quickly. Thanks, until next time, Frank.


Further Reading

The Best Turtle Filters

Keeping Semi-Aquatic Turtles



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