Armored eel

Armored eels were a species of carnivorous eel native to the swamps of the moon Yavin 4. They preyed upon brightly colored lizard crabs.

Behind the scenes
Armored eels first appeared in The Illustrated Star Wars Universe, a Star Wars Legends book showcasing concept art drawn for the films by Ralph McQuarrie, with text by Kevin J. Anderson. The creatures were confirmed to be canon by the reference book Ultimate Star Wars, which was released in 2015.