Holy Cow

The whole fish is a box.

A cowfish does not have scales the way most fish do; it has plates, fused into a rigid hexagonal shell, so that the body cannot bend at all. It swims by fluttering its fins, like a slow, careful helicopter. The horns above the eyes give it the name. The pattern gives it the rest of the name, and this one's pattern, green on gold, every cell edged, is the picture.

Buddy's Reef, Bonaire, on a June morning in 2010, with a macro lens close enough to fill the frame with the flank and the eye. Cowfish are slow, and curious, and will hold still for a photograph if you are slower still. This one did.