The world has about 32,000 species of fish. Freshwater fishes are about 23,000 and saltwater fishes are about 9,000 species. They need food or energy to grow, maintain the body’s function and reproduce. Therefore, a lot of freshwater and saltwater fishes, who are carnivores, herbivores, and omnivores, are foraging for food. A few fishes are planktivores or detritivores, which means they eat zooplankton (small animals who live in water), algae, and other decaying material. Since most of the aquatic species are planktivores or detritivores, they are eating each other’s . There are some fishes that eat phytoplankton (microscopic plants that live in water) and fungi. One of the most unique ways of eating is that clam fishes open the shell of the clam and eat its meat.