The largest pearlfish are about in length. Not much is known about the sexual behavior of worm pearlfish. The worm pearlfish is an uncommon species. Mussels, Eastern Pearlfish, Sea Lampreys, and American Eel's. Nematolebias whitei, the Rio pearlfish, is a species of killifish from the family Rivulidae. Another parasite often found in this holothuroid is the worm pearlfish ("Encheliophis vermicularis"). The worm pearlfish ("Encheliophis vermicularis") is an eel-like fish in the family Carapidae. Pearlfish usually live alone, or in pairs. Worm pearlfish, specifically, prefer the coelomic cavity of the genus "Holothuria" (sea cucumbers).