Should You Keep a Diamondback Terrapin as a Pet?

Characteristics, Housing, Diet, and Other Information

Diamondback terrapin
Clara S. / Flickr / CC By 2.0

Diamondback terrapins are fairly docile turtles that are generally willing to be handled, although they may bite if they feel threatened. It is legal to own terrapins, and they are relatively easy to care for. These reptiles do like the company of other terrapins, though, so it's best to own more than one if you can provide a spacious enough enclosure. Their enclosure must also be large enough to contain several inches of brackish (salty) water in which the turtles can swim.

Species Overview

Common Names: Diamondback terrapin, DB terrapin

Scientific Name: Malaclemys terrapin

Adult Size: up to 8 inches long (females); 5 inches (males)

Lifespan: 25 to 40 years in captivity 

Can You Own a Diamondback Terrapin as a Pet?


It is legal to keep the diamondback terrapin as a pet as long as it is purchased from a licensed captive turtle breeder. It is illegal to capture a wild turtle and keep it for a pet. However, North Carolina and South Dakota have banned all turtle sales. In addition, the U.S. Food and Drug Administration (FDA) prohibits the sale of live turtles with a carapace (shell) that measures less than 4 inches in length.


While wild animals are naturally happier and healthier in their native habitats, it is generally considered ethical to keep captive-bred turtles as pets. As long as terrapins are kept in proper conditions and fed the food they need, these turtles can thrive.

Things to Consider

Even though it is legal to own terrapins, you can't just buy one, bring it home, and put it in a fish tank. Terrapins must be kept in specific conditions and fed foods that will sustain them. It is important to research exactly what a terrapin needs and prepare your home to welcome this pet.

Diamondback Terrapin Behavior and Temperament

These turtles are social and prefer the company of members of their immediate family like parents and siblings. They are known to share resources, like piling atop one another to concurrently take advantage of the best basking rock.

During the day, terrapins enjoy basking in the sun (or under a heat lamp), often in social groups. You can raise a single turtle successfully, but diamondbacks are fairly social and do even better in groups—provided there is enough space for everyone. Chronically overcrowded diamondbacks may feel stressed and nip at one another's tails.


Pet terrapins will require brackish water in captivity that matches their habitat in the wild. Terrapins kept in unsalted freshwater begin exhibiting health problems from the lack of salt.

As aquatic turtles, diamondback terrapins need a tank filled with brackish water that is deep enough for the turtle to swim and dive in comfortably. Look for a 75-gallon or larger tank, and aim for a water depth that is at least three times as deep as the length of the turtle's current shell. They'll also need a wide, flat place to haul out of the water for comfortable group basking, like a rock or small log.

Water filtration is crucial to a diamondback terrapin's environment as these messy eaters usually create dirty water that will lead to skin and shell problems including shell rot. There is a variety of submersible, canister, and traditional water filters to choose from.

Specific Substrate

Crushed coral is recommended for the bottom of a terrapin's tank. It serves a dual purpose as both a substrate (tank flooring) and a calcium supplement. Diamondback terrapins like to bite at the coral, and they benefit from both the added calcium in their diet and the natural wear to their beaks as they crunch it.


Terrapins need a water temperature above 70 degrees; they mustn't get too cold. During the day, white heat lights can be used to add extra warmth to your tank. At night, use a ceramic heat emitter with only blue or red light. Water heaters designed for fish tanks can also be used to keep the water warm.


Like other aquatic turtles, terrapins require UVB lights. UVB spectrum lights that are specifically designed for reptiles should be kept on for about 12 hours a day and positioned roughly 10 to 12 inches from where the turtle basks. This will enable your terrapin to grow and thrive as it would in natural sunlight. Without UVB light, your turtle is extremely likely to develop metabolic bone disease (MBD) and not grow properly.

What Do Diamondback Terrapins Eat and Drink?

Unlike most other pet aquatic turtles, diamondback terrapins primarily eat meat. In the wild, they eat a variety of small aquatic animals and occasionally graze on some plants. In captivity, you can feed them a mix of turtle pellets, dried shrimp, smelt, snails, and other accessible seafood once a day. Feed every other day, once during that day, and promptly clean out uneaten food so it doesn't rot.

Do not feed them meat such as chicken or beef; if they don't encounter the food in the wild, a diamondback terrapin probably won't be able to digest it easily. As turtles go, terrapins are rather messy eaters that will often turn over their food bowls to enjoy eating when and wherever they choose. 

Common Health Problems

In general, diamondback terrapins stay healthy and parasite-free with proper care. The most significant health problem for a diamondback terrapin is shell rot. Another risk for this species is deformities of either the shell or the eye. All of these can occur when the turtle is under stress, receives poor nutrition, or lives in water that has too little or too much salt.

To avoid these issues, choose healthy baby diamondback terrapins born in captivity, provide a varied and nutritious diet, and use a ppm (parts per million) concentration of saltwater that mimics the natural origin of the subspecies you have. This information should be provided by the person you buy the terrapin from.

Size Information

As with many other reptiles, the female of the terrapin species grows larger than the male. Female shells can reach about 8 inches (approximately the size of an average dinner plate), while males' shells only reach about 5 inches in length.

Pros and Cons of Keeping a Diamondback Terrapin as a Pet

Diamondback terrapins are fun pets to keep and watch as they swim and crawl around their tank. They are also easy to handle and make interesting teaching tools for budding herpetologists. The only drawback to owning these turtles is that they do require specific care in terms of water salinity, temperature, lighting, and feeding. Failure to meet their needs can result in stress, various ailments, and even the death of your pet.

Purchasing Your Diamondback Terrapin

When buying one or more diamondback terrapins, choose young turtles that are available from reliable turtle breeders. It's also acceptable to buy adult turtles from someone who has taken good care of them and needs to find their pets a new home.

While it's possible to find diamondback terrapins in the wild, it is not legal to capture them for private ownership. Wild terrapins would not make good pets anyway because they become anxious in confined spaces and don't want to be handled.

Similar Species to the Diamondback Terrapin

 If you’re interested in similar turtles, check out:

  • Do diamondback terrapins bite?

    These turtles rarely bite as long as they are handled gently.

  • How long do terrapins live?

    In the wild, terrapins encounter life-threatening hazards, such as predators and habitat destruction by humans, that can shorten their lifespans. In captivity, these turtles can live up to 40 years with proper care.

  • Do terrapins live alone or in groups?

    In the wild, terrapins tend to live near one another and even hang out in groups when basking on rocks and logs. In captivity, a pet terrapin will appreciate the company of another member of its species as long as the turtles have enough space to not be crowded.