Black Butterfish

Schedophilus medusophagus

The black butterfish (Schedophilus medusophagus), also known as the cornish blackfish, is a medusafish reaching about 50 cm in length, found in the eastern Atlantic from Scandinavia to West Africa and the Mediterranean. Its body is deep and laterally compressed with a dark blue-black to brown coloration and a rounded profile. The skin has a smooth, somewhat slimy texture. As its scientific name suggests (medusophagus means jellyfish-eater), this species has a strong association with jellyfish throughout its life. Juveniles shelter among the tentacles of large pelagic jellyfish, gaining protection from predators while feeding on the jellyfish tissue and associated organisms. Adults become more free-swimming and are found at depths of 50 to 500 meters in midwater, though they occasionally appear in shallower coastal waters. They feed on jellyfish, salps, small fish, and crustaceans. Encounters with this species are uncommon for divers, making sightings particularly memorable. When juveniles are found sheltering beneath compass jellyfish or barrel jellyfish in temperate waters, they provide fascinating behavioral photography opportunities showing this unusual symbiotic relationship.