South American Knifefishes and Electric Eels: Gymnotiformes

South American knifefishes and electric eels can regrow the hind parts of their bodies. They are active at night and hide during the day among plants, in floating meadows, in crevices and holes, and under various kinds of shelter. During the day some species lie flat and motionless on the bottom, imitating leaves. Some species burrow in the sand during the day.

South American knifefishes and electric eels spawn, or release eggs, every few days to every few weeks. Knifefishes reproduce during the high-water season, and eels during the dry season. During courtship, the electrical discharges serve various purposes. Some species form pairs during reproduction, and others form complicated social groups. Some of these fishes build nests, and others lay eggs among plants. Some larvae, the early stage of an animal that must change form before becoming an adult, feed on eggs laid in another batch. Some males guard the young. Males of one type of knifefish hold the eggs in their mouths until the eggs hatch.