Commercially prepared complete diets are available for iguanas, turtles and tortoises and should contain the necessary vitamins and minerals. Otherwise feed fresh foods with a vitamin and mineral supplement. Tomatoes are great for tortoises, but not for iguanas. Spinach should not be fed as it binds up calcium internally. It is doubtful that any herptile is a total vegetarian.
Most primary vegetarians are probably truly omnivores .
Many, such as tortoises and iguanas, also tend to eat insects and invertebrates. Some may even eat an occasional mammal. Herptiles that are carnivores eat proteins such as rodents, insects and invertebrates. Other proteins include guppies, goldfish, eggs and even other herptiles. A snake will eat a frog.