A box with horns. The body is a rigid armored shell of fused plates with a pair of spines above the eyes, another pair at the rear, and - the detail that names it - a single backward-pointing thorn in the middle of the back. Blue lines and spots wander over an olive to yellow ground, and the whole thing moves by sculling with fins so small they look borrowed.
The armor is a trade. Nothing about this fish is fast or flexible, and it does not need to be: a rigid box is hard to bite and awkward to swallow. What it loses in maneuvering it gains in not having to. It hovers over rubble and seagrass, blowing jets of water at the sand to expose worms and small crustaceans.
The second defense is chemical. Boxfishes release ostracitoxin from the skin when badly stressed, potent enough to kill other fish in a confined space - which is why one dying in a bucket or a home tank can take everything else with it. In the sea it is harmless to watch, and slow enough that a photographer gets several attempts.
- boxy armored body with a pair of horns over the eyes and another pair at the rear
- single backward-pointing spine in the middle of the back
- blue lines and spots over an olive to yellow ground
- sculls with tiny fins, body held rigid
