5 to 9 inAdult shell length
25 to 40 yearsLifespan with good care
60 galWater at full size
AquaticNeeds a tank with a dry dock
Protected or permit-only in most coastal states. Captive-bred with paperwork only.
The enclosure at full size
Males stay around 5 inches and females reach 9, so size the tank for the female. A breeder who has kept them for decades uses a 40-gallon tub for one adult female or two males; 60 gallons gives room for deeper water and a bigger filter. A tub or stock tank works as well as glass. Hatchlings can share a 20-gallon long with 3 to 4 inches of water. Adults need a dock that is firmly anchored, since a 9-inch female will tip a floating one.
Water
Keep water at 76 to 78°F on a guarded heater. Terrapins live in brackish water, and the same breeder runs tanks at about a quarter of seawater strength with occasional soaks in fresh water for drinking. Others raise captive-bred animals in fresh water with a little aquarium salt. Either way, poor water quality is the leading cause of illness in captive terrapins, so oversize the filter and change water weekly.
Temperatures
Basking surface in the mid 80s°F under a 50 to 75 watt spot lamp, measured on the dock. Water 76 to 78°F. Larger animals in a cool room may need a night heat source on a timer.
Light
A full-spectrum UVB bulb over the dock on a 12-hour timer, within the distance the maker states, and replaced on the maker's schedule whether or not it still glows. A terrapin that cannot bask under UVB cannot use the calcium in its food.
Diet
Mostly animal food: commercial turtle pellets, dried brine shrimp, thawed salad shrimp, snails and other molluscs, which it crushes with a broad jaw. Hatchlings eat a little every day and should have a calcium block or cuttlebone in the water to graze. Adults eat less often. Feed in a separate tub if you want the tank to stay clean.
Handling
Most are docile and rarely bite, but a large female has a big head and strong jaws and should be handled with care. Wild-caught animals are high-strung and do badly in captivity. Wash hands after every contact and keep tank water away from mouths.
The law
Federal law bars the sale of turtles under 4 inches as pets. Florida's Fish and Wildlife Conservation Commission ended all take in March 2022 and bars possession without a permit. Maryland limits noncommercial possession to three and bans commercial take. Most other Atlantic and Gulf states protect them too. Buy captive-bred, keep the receipt, and check your state agency first.
Sources
Where to go next
Read the 4-inch rule, explained before buying any turtle, and the basking, heat and UVB guide before the first day home. Nothing here replaces a reptile vet; the directory lists them by state, and the law pages cover your state.
