It is difficult to provide a well balanced diet for companion aquatic and semi-aquatic turtles. Although there are species-specific dietary needs that need to be respected, there are general guidelines that can be applied to all omnivorous species. Most companion aquatic and semi-aquatic turtles are omnivorous, and their diet should ideally be composed of fresh vegetal products and fresh animal protein sources. The proportion and type of protein sources will vary according to the species of turtle.

Since most commercial turtle feeds are not proven to be reliable long-term diets (lack of product information and labeling, inappropriate nutrient content and proportions, lack of scientific studies), some turtle fanciers prefer to prepare their own turtle food. With an attention to detail, it is possible to provide a fresh and balanced diet to turtles and to prevent common malnutrition problems.