Angler fish

Angler fish is a name used for more than 200 different predatory fish species that all use a very characteristic method to catch their prey. The Angler fish has developed a modified first spine known as the illicium. The illicium is attached to the first or spinous dorsal fin and protrudes over the eyes of the Angler fish. The illicium is equipped with a fleshy growth named esca and the Angler fish can wiggle the esca back and forth to use it as bait. Other predatory fish will be lured to this bait and promptly devoured by the Angler fish as they come close enough to its mouth. One of the Angler fish species, the Netdevil, even has some additional growths on the chin to look extra attractive to prey. A predatory fish doesn’t have to be small to be considered prey by the Angler fish, since the Angler fish can distend its jaw and swallow fishes that are twice as big at it self. To digest these large preys the Angler fish have bones that are thin and flexible and a stomach that can be expanded to an enormous size.

All the known Angler fish species belong to the order Lophiiformes; the bony fish order. A majority of the species belong to deep-water dwelling fish families that live in the oceans' aphotic zones. There are however also some Angler fish families that contain a few shallow water Angler fish species, such as the family Lophiidae that contains the Goosefish/Monkfish, the family Ogcocephalidae that contains the Batfishes and the family Chaunacidae that contains Seatoads/Coffinfishes. In the family Antennariidae, all the Angler fish species inhabit shallow waters. They are known as Frogfishes.

Lophiidae Angler Fish

The family Lophiidae was the first type of Angler fish known to science. This is not hard to understand, since a majority of the other Angler fish families’ lives far down in the deep ocean where it is impossible to study them without special equipment. In the family Lophiidae you will find the Goosefishes. These fishes belong to the suborder Lophioidei and genus Lophius and are recognized on their wide and flattened head and broad mouth. The eyes are turned upwards and the teeth are sharp and pointy. A goosefish can grow larger than 5 feet (1.5 meters) and catch large predatory fish as well as diving birds.

Unlike most other types of Angler fish, the goosefishes are equipped a slender finray that is accompanied by one or two other long rays on the head, and one or several extra rays behind these main rays. This multitude of rays distinguishes them from most other Angler fish species. A goosefish will spend a lot of time laying flat on the bottom where it can stay virtually invisible and wait for unsuspecting prey to swim by. The goosefish is camouflaged by a marbled skin coloration that blends in with the bottom. The body shape will also aid to the camouflage; the outline of the body is made less visible by a fringe of branched skin flaps.

Ogcocephalidae Angler Fish

The family Ogcocephalidae is where you can find the Batfishes. These fishes are famous for their “walking” ability. They are so adapted to a life at the bottom of the ocean that they walk using their pelvic and pectoral fins rather than swim. The pectoral fins of this Angler fish have developed arm-like stalks and the pelvic fins are found in front of these pectoral fins. The 62 different known Batfish species belong to nine different genera. In shallow waters, the most commonly found Batfishes are the Polka-dot Batfish and the Shortnose Batfish.

A dark coloration keeps Ogcocephalidae Angler fishes camouflaged on the murky bottom as they wait for their prey to swim up to them. The skin is very rough and durable. The body is very flat with a depressed triangular head and the dorsal as well as the anal fin is very short. The anal fin is situated far behind the anus and the caudal fin is rounded. On the upper parts of the body of this fish you will find pointy bony tubercles. Similar tubercles are also situated on the tail. You will find the gill openings if you look right behind the base of the pectoral “arms”.

Ogcocephalidae species feed chiefly on smaller prey, such as worms, snails, crustaceans and clams. Just like all the other Angler fish species, they use an illicium to attract prey. The snout of the Ogcocephalidae species has developed a blunt rostrum under which a cavity is found. When the fish do not use its illicium to attract prey, it will keep it hidden and protected inside this cavity.