The only catfish on a coral reef, and it announces itself as a ball. Juveniles gather in a dense sphere of hundreds of fish that rolls across the sand, boiling over itself, feeding as it goes - one of the most photographed sights in this sea and one of the most misread. It is not a school being social. It is a defense: a shape too large to swallow and too confusing to pick a fish out of.
Adults break it up. They spend the day hidden under ledges and hunt alone at night, using four pairs of barbels to taste and feel for worms and crustaceans in the sand. They also detect the weak electric fields of buried prey, so a shrimp holding still is not hidden from them.
The fish is genuinely dangerous, and the ball is the reason: it is beautiful, it is slow, and it invites a hand. The first spine of the dorsal fin and of each pectoral fin is serrated and venomous, the sting is severe, and deaths have been recorded. Hot water at 45 C (113 F) breaks the venom down; then a hospital, because the spines break off in the wound and it infects readily.
In the eastern Mediterranean this is now an established Lessepsian migrant, and beachgoers there are learning what divers here already know.
The genus. Plotosus Lacepède 1803 - plōtós (swimming or floating). ETYFish
- eel-like body with two cream stripes on brown
- four pairs of barbels around the mouth
- juveniles in a dense writhing ball, adults solitary and hidden
- no separate tail fin - dorsal, tail and anal run together to a point
- length up to 35 cm
Why it's threatened
Threat classification from the IUCN Red List.
