Blue Chromis in Cozumel
Blue Chromis (Chromis cyanea) in Cozumel: how to identify it, where it is reliably seen, and what it is commonly confused with.
Electric blue, forked-tailed and always above the reef rather than in it. On a wall dive they hang in the blue in loose clouds, dropping back into the coral the moment something large passes.
Quick ID
| Scientific name | Chromis cyanea |
|---|---|
| Group | Colourful Reef Fish |
| Typical size | Up to 15 cm |
| Depth range | 3–60 m |
| When to see it | Year-round |
| Active | Day |
| Conservation status | Least Concern |
How To Identify It
Brilliant blue with black edging along the top and bottom of the deeply forked tail. Small, slender and unmistakable in good light.
Where You Will See It In Cozumel
Blue Chromis works the 9 to 121 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 Coral Princess, El Islote and El Mirador — all shore entries, so you dive them on your own schedule.
On an ordinary beginner boat dive. It should be within reach at Palancar Gardens, Paradise, Punta Dalila, San Clemente and Yellow House. No advanced certification needed.
Deeper, and on the walls. It is also plausible on Punta Sur, Punta Tunich, San Francisco Wall and San Juan.
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
Plankton feeders. They face into the current a metre or two above the reef and pick food out of the water, retreating into the coral when threatened. The colour looks grey at depth without a light — blue is the first colour water takes away.
Commonly Confused With
- Brown chromis — Same shape and habit, but olive-brown with a yellow tail edge.
- Creole wrasse — Larger, purple, and travels in bigger moving schools rather than hovering.
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.
Blue Chromis Photos
Frequently Asked Questions
Why do blue chromis look grey when I dive deeper?
What do blue chromis eat?
Where do you see blue chromis in Cozumel?
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