If you’ve ever dove on a coral reef – or watched the Cayman Reef Live Cam here on explore.org, you may have seen a red and white fish with massive eyes hanging out close to the shelter of a big coral head or under a ledge…
These sneaky, big-eyed fish are Squirrelfish (Holocentrus adscensionis) and they are the best at finding shadows on sun-soaked tropical reefs.
A hiding squirrelfish waits in the shadows of a coral until nightfall. (Image: marinebio.org)
Why the big eyes? Squirrelfish are nocturnal, which is both why they spend much of the day in the shadows and why they require bigger eyes for better night vision. Their red coloring is also helpful for being stealthy at night because red light is the first color in the light spectrum to disappear when light levels drop. As a result, the Squirrelfish looks dark, just like the shadows, and is difficult for predators to see while it is hunting for crabs and other crustaceans at night.
Look for their limited daytime activity on the Cayman Live Reef Cam to glimpse one of the few Caribbean nocturnal reef fish!
