LizardfishesSynodontidae

It has teeth on its tongue. The jaws of a lizardfish are lined with them, the roof of the mouth carries more, and there is a patch on the tongue itself, so the entire inside of the mouth is a bed of needles. They also hinge. Pressure from the front folds them back and lets prey slide inward; pressure from behind sets them upright, and what has gone in does not come out. There is no cutting and no chewing anywhere in this: prey goes down whole and head first, and a lizardfish will take a fish that looks much too large for it.

A good deal of what it eats has only just arrived. A reef is restocked continuously by young fish coming in out of the plankton and settling on the bottom, and the lizardfish is what is waiting where they land, on the sand and rubble at the edge of the coral rather than in it. The attack is vertical. It leaves the bottom, takes the fish in the water above, and is back on the same patch of sand facing the same way.

Its own young drift for a long time before they do any of that. Lizardfish larvae are transparent, with a row of dark blotches inside the gut showing through the body, and they stay in the plankton long enough that the same species turns up on both sides of an ocean. One relative of theirs went a different way entirely and became food: Bombay duck, dried by the ton and sold across South Asia, is a lizardfish and has nothing to do with ducks or with Bombay poultry.

Six species are listed here. The reef species stop around twenty centimeters and the largest, living out on open sand and mud rather than beside coral, reaches about fifty. Telling them apart is genuinely hard and the useful marks are all on the head, so a photograph taken from in front is worth more than a photograph of the whole fish from the side.