<P> Juvenile fish go through various stages between birth and adulthood . They start as eggs which hatch into larvae . The larvae are not able to feed themselves, and carry a yolk - sac which provides their nutrition . Before the yolk - sac completely disappears, the tiny fish must become capable of feeding themselves . When they have developed to the point where they are capable of feeding themselves, the fish are called fry . When, in addition, they have developed scales and working fins, the transition to a juvenile fish is complete and it is called a fingerling . Fingerlings are typically about the size of fingers . The juvenile stage lasts until the fish is fully grown, sexually mature and interacting with other adult fish . </P> <P> Ichthyoplankton (planktonic or drifting fish) are the eggs and larvae of fish . They are usually found in the sunlit zone of the water column, less than 200 metres deep, sometimes called the epipelagic or photic zone . Ichthyoplankton are planktonic, meaning they cannot swim effectively under their own power, but must drift with ocean currents . Fish eggs cannot swim at all, and are unambiguously planktonic . Early stage larvae swim poorly, but later stage larvae swim better and cease to be planktonic as they grow into juveniles . Fish larvae are part of the zooplankton that eat smaller plankton, while fish eggs carry their own food supply . Both eggs and larvae are themselves eaten by larger animals . </P>

What is the young one of fish called