Fuzzy Filefish

The trick this fish uses is not being worth a second look. It is under 10 cm, mottled brown and olive, and it lives over weedy rubble and broken bottom rather than clean coral, which is the part of the dive nobody is photographing.

It is a filefish, and the family name is literal: the skin is covered in minute scale spinules and is rough as a file. Filefishes also carry the locking spine their triggerfish relatives are famous for: the long first dorsal spine folds into a groove on the back, and a small second spine drops in behind it and jams it upright. Backed into a crevice with the spine locked and the belly flap flared, the fish cannot be pulled out.

Identify it by shape, not by color. The body is a short, deep, strongly flattened diamond, the snout profile is slightly concave, and the mouth is tiny and sits right at the front. The first dorsal spine sits above the eye. Ground color runs pale gray to olive brown with darker mottling and faint bars, but filefishes shift pattern quickly, so work from the outline and the snout, not from a remembered color.

The species name means thread-bearing. Paramonacanthus is a genus built on the differences between the sexes: males run to longer snouts, drawn-out front lobes on the second dorsal and anal fins and patches of enlarged spinules on the tail base, while females stay plainer. Two fish of one species can look like two species.

It is a western 🌊 Indian Ocean animal, recorded from the 🌊 Red Sea south to Zanzibar and out to the 🇸🇨 Seychelles; the guide's 🌊 Red Sea photograph was taken in Naama Bay. No published depth range exists for it and nobody has studied what it eats: it sits among the small omnivores taking invertebrates and algae off the bottom.

Be honest about your chances. This is less a rare fish than an unnoticed one, and most people who have swum past one here logged it as a small brown something over the rubble.