Frogfish

Scientific name : Antennariidae

Here is a very strange fish family, belonging to the class Osteichthyes (bony fishes) and to the order Lophiiformes. It includes animals almost unable to swim, very slow moving, extremely specialised for ambush predation. They are a perfect subject for fish watching and photography, because they are very slow and often, unaware of divers, they behave normally... only it is not easy to see them. Absolute stillness, and a cryptic colour, make it practically invisible. In our area, Lembeh strait is a very good site for frog fish-watching. Frog fishes have a soft, rounded body, soft skin. The dorsal fin has a first ray transformed into a mobile stalk, the illicium or stork, carrying a lure (esca) on its end. This is used to attract preys, usually other fishes. The illicium lenght and esca shape are good diagnostics to separate the different species. The mouth is very large, opened upward. Also the stomach can be dilatated. The 2nd and 3rd dorsal spines are surrounded by 2 fleshy appendages on the head, followed by a soft fin. The 2nd is mobile. Pectoral fins have sort of a elbow joint, and strong rays, fit for grabbing. Using those fins, often frog fishes move around along the bottom, literally walking. Some species can have skin appendages for camouflage. Frog fishes live normally in coastal environments, in sheltered, calm waters like in bay or lagoon. It is possible to find them along the external reef, one species lives in open sea. Often they live close to sponges, seaweeds, abandoned human objects. They feed primarily on fishes, that they attract using their lure. When the prey is close, with a rapid movement (1/100 second) the mouth opens and sucks it. The female frog fish usually releases planktonic eggs in large jelly masses. Only few species have benthic eggs, guarded by the female. Once seen a frog fish, confusion is difficult. A somehow similar group, at least for the life style, is the family Scorpaenidae (scorpion fishes). Those latter are always spiny, they have poisonous spines on the dorsal fin, often scattered spines on the body, they have no fleshy appendages neither esca. Frog fishes are never spiny.