Although a favorite with many divers it would seem that not much is known about the crocodile fish. Crocodile fish are members of the same family as lionfish, scorpionfish, and stonefish (scorpaenidae) and belong to a subgroup called flatheads. When found underwater these fish seem gentle and unafraid. They are a photographer’s dream because you can get very close to them and they don’t move. 

They get their name crocodile fish because of their appearance rather than their temperament. They have an elongated mouth with a protruding jaw, big round eyes on top of their head, and appear lazy, all characteristics very similar to their land-living namesake. Their long depressed body is a mottled brownish-green color allowing them to blend in perfectly with the sea bed where they mostly spend their time.  Juveniles are usually black and develop this colouration as they reach adulthood. They have a frilly flap like a tasseled curtain known as a lappet on top of their pupil which breaks up the outline of the iris and greatly improves their camouflage. They are able to control this lappet to cover more or less of the eye as desired. The crocodile fish can grow up to between 70cm and 1m long.

Crocodile fish are normally limited to the western Indian Ocean and the Red Sea. However, this species has now invaded the Mediterranean Sea through the Suez Canal. They are mostly found on sand, in which they can be partially buried, or rubble in sheltered bays and lagoons at depths between 1m and 40m. They are also often found on wreckage.

They are an ambush predator with a liking for crabs, shrimps and small fish. As prey unwittingly approaches the crocodile fish will make a rapid lunge opening its strong jaws wide and extending its mouth in a net-like fashion around the prey. They then clamp their jaws shut with the prey inside. They have a symbiotic relationship with the cleaner wrasse responsible for cleaning its teeth but occasionally mistakes are made and the wrasse gets eaten as well. The crocodile fish has 10 sharp dorsal spines for its own protection against predators. 

Not much at all is known about the mating habits of the crocodile fish. They live a very solitary life though it is assumed that males and females must come together at some time to reproduce. Scientists currently believe the population doubling time to be anywhere between 4½ to 14 years.