Larval eels (this one is Xenomystax congroides) are known as leptocephalus larvae. The name reveals a character shared by all of these larvae, leptocephalus means small head. Leptocephalus larvae are largely transparent and may remain as larvae in the water column for as long as three years. For many years, science thought that these larvae were species of fish unto their own. Gradually, ichthyologists began to realize that they were larval eels. Often, leptocephalus larvae are many times smaller than the adults. It is interesting to consider just how large adults specimens of large leptocephalus larvae (one specimen just shy of six feet) might grow. Much speculation has gone into these large specimens and the size of the adult eels, however, no one knows because an adult eel, associated with the larvae, has yet to be described. The ocean undoubtedly hold many more secrets and discoveries, this is just one of them. This specimen was trawled between 500 meters depth and the surface in the Gulf of Mexico, 2015.