Terrapins are freshwater turtles who belong to the taxonomic family Emydidae. While 350 turtle species exist worldwide, there's only one species of terrapin -- although this species is divided into seven subspecies. Until the 1930s, these creatures were hunted for food and nearly became extinct as a result. Today they're once more populous in the wild, as well as being fairly common pets.
As omnivorous creatures, terrapins can eat a wide range of different foods. Commercially available terrapin foods are a good basis for a well-balanced diet, but your pet should be fed fresh foods, as well. In the wild, these turtles almost exclusively eat live prey, so you should feed your terrapin some low-fat meat, as well as fish and shellfish. Oily fish, such as tuna and mackerel, is generally well-received and is full of vitamin D. He should also eat fruits and vegetables, including lettuce, watercress and strawberries. Supplement his diet with a commercial terrapin vitamin and mineral product to ensure he gets enough calcium and other essential nutrients.