Baby eels are practically invisible. A Leptocephalus (meaning "slim head") is the flat and transparent larva of the eel. They grow about 60-300 mm. These fishes with a leptocephalus larva stage include the most familiar eels such as the conger, moray eel, and garden eel, and the freshwater eels of the family Anguillidae, plus more than 10 other families of lesser-known types of marine eels. They appear to feed on tiny particles floating free in the ocean, which are often referred to as marine snow. en.wikipedia.org