Harlequin Bass in Cozumel

Bold black rectangles on a pale body and a long pointed snout, usually sitting motionless on rubble. It looks painted rather than camouflaged, but on broken ground the pattern breaks the outline up completely.

Quick ID

How To Identify It

Cream to yellowish with a grid of dark rectangular blocks along the back and sides, a pointed snout, and yellow tinting on the lower body.

Where You Will See It In Cozumel

Harlequin Bass works the 6 to 81 foot band. On this island that means the sheltered west-coast reefs, and the shallow east-side entries when the sea is flat — these are the sites where the depth and the habitat line up for it.

Without a boat. It is worth looking for at Tikkila Shallow, Chankanaab Shallow and Chen Rio — all shore entries, so you dive them on your own schedule.

On an ordinary beginner boat dive. It should be within reach at Molas Shallow, Palancar Gardens, Paradise, Punta Dalila and San Clemente. No advanced certification needed.

Deeper, and on the walls. It is also plausible on Los Atolones, Maracaibo, Palancar Bricks and Palancar Caves.

Conditions change the odds more than the site does — the current, the time of day and how much the group has already stirred up the sand. Ask your guide what they have been seeing that week.

Behaviour

An ambush predator on small fish and crustaceans. It sits still, propped on its pectoral fins, and takes prey that comes within reach.

A simultaneous hermaphrodite, like the other Serranus basses — pairs alternate roles when spawning at dusk.

Commonly Confused With

• Tobacco basslet — Soft brown bands, not hard black blocks, and it hovers rather than rests.
• Sand diver — Much longer and more cylindrical, lies on open sand.
• Juvenile grouper — Rounder head and no rectangular grid.

Diving Etiquette And Safety

Keep fins off the reef and hands to yourself. Nothing here needs to be touched, moved or provoked to be seen well.

Part of the Cozumel marine life guide · see Cozumel dive sites · plan your Cozumel dive trip

Photo © Stephen Hoerler, courtesy of the Cozumel Coral Reef Restoration Program, used with permission.