Undulating in a dense mass that helps protect them from predators, this school of juvenile striped eel catfish (Plotosus Lineatus) was spotted in Amed, East Bali‘s Jemeluk Bay by Abyss Dive Center Bali instructor Marie-Laure Vergne. From Fishes of Australia:

A distinctive striped catfish with an eel-like body and mouth surrounded by 4 pairs of barbels. The stripes become less distinct in adults. Brightly-striped juveniles often form dense schools of hundreds of individuals that appear to move as one.

The serrated dorsal and pectoral-fin spines are highly venomous and can inflict a very painful wound.

Abyss Dive Center Bali writes: “The young ones can only produce a mild version of the venom, tingling the fingers of the people putting their hands in the school (which we don’t recommend you do!)”

Try rewatching the video, picking one fish and following it the entire time. Then pick another fish and watch the video again. The juvenile striped eel catfish seem to cycle through positions within the school as the entire swarm moves forward.

TIL: These striped creatures are just one species of the forty-one species of eeltail catfish.

Watch these fish swarm videos on TKSST next:
• Predators Attack Fish Bait Ball
• The Gathering Swarms: Sardine Run off the coast of South Africa
• Secrets of Schooling: Investigating the collective behavior of fish
• Flying Fish, hunted underwater and in the air.