Long-term maintenance of most amphibians requires live food. Most adult terrestrial and aquatic amphibians feed on invertebrates (animals that do not have backbones), including earthworms, bloodworms, black worms, white worms, tubifex worms, springtails, fruit flies, fly larvae, mealworms, and crickets. However, some amphibians feed on vertebrates (animals with backbones) and require live minnows, guppies, goldfish, or newborn mice or rats. Most invertebrates raised as food sources lack the proper ratio of calcium to phosphorus needed to maintain healthy bones. (Earthworms are the exception.) They also lack vitamins that help prevent other diseases. For these reasons, owners of amphibians must include vitamin and mineral supplements in the diet to prevent nutritional disease. This is commonly done by gut loading, or feeding commercially available diets high in calcium to insects 48 hours prior to feeding the insects to your pet. It can also be done by coating insects (also known as dusting) with powdered multiple-vitamin preparations that include vitamin D3 and calcium. Your veterinarian can provide appropriate guidelines for supplementation.