These strange-looking creatures live in European waters. They are eels that are transparent when they are young (as larvae), but as they grow they become more of a greenish-brown color.

Leptocephali are the larval stage of eels and other related fish, and they play a crucial role in the marine ecosystem. These unique larvae are characterized by their flattened, transparent bodies ...

Once they’ve laid their eggs, European eel larvae ― which bob around like tiny transparent leaves ― ride the currents for thousands of miles until landing on the shores of Eastern Europe.

Kindai University in Osaka Prefecture said it achieved full-cycle aquaculture of Japanese eels after raising larvae from eggs spawned by artificially incubated adults. The institution said it ...