Nassau Grouper in Cozumel

A heavy-bodied grouper with five dark bars running vertically down a pale body, a black saddle on the tail base, and a dark band through the eye. The whole pattern can wash out or intensify within seconds.

Quick ID

Where You Will See It In Cozumel

Nassau Grouper is tagged on reef profiles right along the west coast, across a depth band of roughly 16 to 98 feet.

Without a boat. It turns up at Chankanaab Shallow and Playa Corona — all shore entries, so you dive them on your own schedule.

On an ordinary beginner boat dive. It is recorded at Las Palmas, Palancar Gardens, Paradise, Punta Dalila and Yellow House. No advanced certification needed.

Deeper, and on the walls. It also shows up on Palancar Caves, Palancar Horseshoe, Paso del Cedral and Punta Sur.

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

Sedentary and often approachable, which is precisely why the species collapsed across the Caribbean — it aggregates predictably to spawn and was fished out at those aggregations. Cozumel individuals are frequently tolerant of divers at a respectful distance.

Commonly Confused With

• Black grouper — Black grouper carry a rectangular chain-link pattern rather than clean vertical bars, and no black saddle on the tail base.
• Tiger grouper — Tiger grouper have oblique, slanted bars and a more pointed head.

Diving Etiquette And Safety

Critically Endangered and protected. Do not feed, corner or crowd. The black saddle on the tail base is the identification feature worth photographing for citizen-science reporting.

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

Photo: NOAA OAR/National Undersea Research Program, Public domain, via Wikimedia Commons.