Ichthyoplankton (from Greek: ,
ikhthus, "fish"; and πλαγκτός,
planktos, "drifter") are the
eggs and
larvae of fish. They are usually found in the sunlit zone of the
water column, less than 200 metres deep, which is sometimes called the
epipelagic or
photic zone. Ichthyoplankton are
planktonic, meaning they cannot swim effectively under their own power, but must drift with the 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.