A yellow box with four horns: a pair above the eyes and a pair at the rear corners, on a body built of fused bony plates that cannot bend. The fins are comically small and never stop moving, because they are the only part of the animal that can.
Hunting is done with water. The fish hovers nose-down over sand and fires a jet from its mouth to excavate the sediment, exposing worms and small crustaceans, then picks them off - the same technique the triggerfishes use with their teeth, done with plumbing instead.
The horns are structural, not weapons. A predator that takes a boxfish has to swallow a rigid object considerably wider than it looks, and the horns make the shape awkward from every angle. They wear down with age and regrow.
The backup is ostracitoxin, released from the skin when the fish is badly stressed, potent enough to kill other fish in a confined space. That is an aquarium problem rather than a reef one - and it is also why an adult cowfish can spend its day drifting slowly in the open, in plain view, doing nothing to hide.
The species. Lactoria cornuta (Linnaeus 1758) - horned. ETYFish
- boxy armored body with a pair of long horns above the eyes and another pair at the rear
- yellow to olive with blue-white spots, fins tiny and constantly working
- hovers nose-down over sand, blowing jets of water at the bottom
- length up to 46 cm
Why it's threatened
The impact of fishing activities on the global population of this species is unknown but is not suspected to be driving global declines approaching 30%.
Threat classification from the IUCN Red List.
