Antennarius commerson or also known as commerson's frogfish, is a fish of the family Antennariidae in the order Lophiiformes. It has a very wide distribution in the waters of the Indian and Pacific oceans. They are usually found in large open caves and sometimes it is also possible to see them in the pylons that make up the docks.
The maximum size Antennarius commerson reaches is 35 cm in length. Their body is orange, although sometimes we can also find black specimens. Not only are they cryptic, but they are also masters of camouflage, masquerading as a sponge or some other part of the reef. This means that we may well be passing right in front of them, and not be aware of their presence. This mimicry with the sponges of adult specimens is not only based on coloration and texture, but the fact that the specimens are usually completely immobile, therefore very often go completely unnoticed. Juveniles, unlike adults, do not base their strategy to go unnoticed as if their whole body were a single sponge, but perhaps because of their size, additionally seek shelter under large coral ledges.
A highly specialized structure, originally derived from the dorsal fin, is a common feature of the species belonging to the order Lophiiformes. This structure is an apparatus for attracting prey, and consists of two parts. A long thin rod that sits on the snout of the animal, and at the end a fleshy bait that mimics a small fish or worm. The specimen will realistically move the bait, attracting prey to the vicinity of its mouth. Once within reach of the specimen, the prey will be sucked instantly by a very fast movement and opening of Antennarius commerson's mouth.Photos: