leptocephalus

noun, plural lep·to·ceph·a·li [lep-tuh–sef–uh-lahy] /ˌlɛp təˈsɛf əˌlaɪ/.

1. a colorless, transparent, flattened larva, especially of certain eels and ocean fishes.

noun plural -li (-ˌlaɪ)

1. the slender transparent oceanic larva of eels of the genus Anguilla that migrates from its hatching ground in the Caribbean to European freshwater habitats