Longsnout Mojarra

The mouth of this fish comes out of its face and points at the ground.

At rest it looks ordinary. When it feeds, the whole jaw apparatus slides forward and down into a tube about as long as the head is deep, and the fish drives it into sand like a probe, takes a mouthful of sediment, and withdraws. Inside, the sand is sorted: worms, small crustaceans and bivalves are kept, the grains are ejected back out through the mouth and gills in a small cloud.

That is the whole family in one piece of anatomy, and it is why mojarras are found over open sand and lagoon bottom rather than on the reef. It is also why they are so hard to tell apart at a glance. They are all bright silver, all deep-bodied, all doing the same job, and identification comes down to snout length, fin markings and the shape of that extended mouth.

This is the largest of them here, up to forty-four centimeters, with the longest snout and a darker margin along the rear edge of the tail. It works shallow sand and the edges of seagrass, usually alone or in small loose groups, moving slowly and stopping every few meters to take another mouthful of the bottom.