Fish larva
The tiny early stage of a fish after hatching, often transparent and very unlike the adult.
Also: larvae, yolk-sac larva
Most fish hatch as larvae, a few millimetres long, often see-through, with a yolk sac that feeds them for the first days. They drift with the plankton and change shape, grow fins and develop scales before turning into juveniles that look like small adults. Eel larvae, called leptocephali, are flat and leaf-shaped and drift for many months. Larvae suffer huge losses to predators and hunger, and the number that survive each year largely decides how many fish later join a fishery.