Hairy frogfish

The name is a colour form, not a species: hairy frogfish and striated frogfish are the same animal, the “hairy” ones being individuals whose dermal appendages have run long. To about 25 cm but usually nearer 10. The character that settles the identification is the esca — the lure at the tip of the rod — which here is two to seven elongate, cylindrical, worm-like appendages, an unmistakable polychaete imitation, and it regrows if lost. The rod itself is about the same length as the second dorsal spine. The skin carries close-set forked spinules and numerous cirri, hypertrophied into the shaggy coat of the hairy form; males generally carry longer filaments and stronger colour than females. Colour is useless here. Individuals run yellow, orange, green, red, grey, brown, white or solid black, with zebra banding and lines radiating from the eye, and a black animal has been documented turning yellow-striped over about five weeks. What it lacks is ocelli, which is a useful negative. The confusion is with the hispid frogfish, and the esca settles it: worms here, a single bushy pom-pom there.

Sand, rubble, mud, seagrass and sponge gardens, from the shallows to over 200 m though typically under 40. It does not chase. It sits, works the rod to animate the lure, and takes the prey with a strike of about six milliseconds — among the fastest feeding movements measured in any vertebrate — the mouth expanding twelve-fold and the prey arriving on the inrush of water. It can swallow animals approaching twice its own length. It walks on its pectoral and pelvic fins, either alternately or in a gallop with both pectorals together. Before spawning, the pair marches across the bottom with the female leading and swollen to roughly twice her normal size, and the eggs go into a ribbon-like gelatinous raft.