The larvae of freshwater mussels, called glochidia, fasten themselves to the gills or skin of fishes and ride about on them. Then they drop off and burrow in the bottom. Barnacles have distinct larval stages called nauplii and cyprids. These larvae swim and drift great distances before fastening themselves to solid objects and becoming adults. Larvae of many water animals are important food for fishes.
Most insects have larvae more or less distinct from the adults.
Larvae that undergo incomplete metamorphosis change directly to the adult stage. Such larvae are often called naiads if they belong to water insects. If they belong to land insects, they are called nymphs. The caterpillar of a moth or butterfly, the grub of a beetle, the hellgrammite of a dobsonfly, and the maggot of a fly are insect larvae with complete metamorphosis. Such insects pass through a pupal stage before becoming adults.