Many freshwater turtles in the wild eat primarily animal matter but also consume some plant material. Some species may be carnivorous when young and shift to omnivorous or herbivorous feeding patterns as adults. Most aquatic turtles cannot be considered strict carnivores, because they consume at least some plant material.
Many commercially available turtle feeds are available, although their nutrient content can vary widely. These products are usually manufactured as extruded or pelleted diets and contain 30–50% protein. Such diets may be appropriate for carnivorous and omnivorous turtles, although the more omnivorous species would benefit from the addition of some fruits or vegetables.
Young turtles should be prevented from growing too fast to prevent the carapace from pyramiding—a situation that occurs when the scutes (keratin-containing segments of the shell that are typically shed as the turtle grows) are not shed quickly enough from the carapace (upper part of the shell) and build up into a pyramid shape. Early development of an abnormal carapace configuration may become permanent. If no artificial diet is available, turtles should be fed their natural diet or a simulated comparable diet. Feeding carnivorous species shrimp, for example, has been successful.
If a commercial diet cannot be obtained, a proven gel food for carnivorous and omnivorous turtles can be made from the following mixture:
water (270 g)
gelatin (34 g)
corn oil (11 g)
spinach (23 g)
cooked sweet potato (23 g)
trout pellets (50 g)
vitamin/mineral supplement (6 g)
The gel food contains on a dry-matter basis 47% protein, 14% fat, 1.5% calcium, 0.55% phosphorus, vitamin A at 10,000 IU/kg, vitamin D3 at 1,000 IU/kg, vitamin E at 279 IU/kg, and vitamin C at 280 mg/kg.
