Frogfish, also known by the scientific name Antennariidae, are a family of anglerfish found in tropical and subtropical oceans around the world. They are known for their striking visual characteristics and are named for their squat, amphibian-like appearance as well as their primary means of locomotion — using their pectoral fins to "walk" along the sea floor. With a variety of camouflage techniques and a specially adapted spine that resembles a lure on a fishing pole, these fish are highly effective ambush predators. They can be found in some home aquariums, but are difficult to care for and may eat tank mates.
The Antennariidae family is made up of about 50 species that vary widely in size and appearance. Even members of the same species can appear quite different, and color variations among the same variety of frogfish once led scientists to mistakenly believe there were more than 160 species in the family. They can range in size from a little more than an inch (about 4.3 cm) to 15 inches (about 38 cm), though most species are toward the smaller end of that range. Members of the Antennariidae family can be found in tropical seas around the world, mostly in coral reefs or coastal areas with shallow waters.
Most species in the family have highly specialized camouflage patterns that closely resemble parts of their habitats. For example, the sargassum frogfish, scientifically named Histrio histrio, has fleshy appendages that help it blend in with sargassum seaweed. Individual fish can also change color over time, making these types of fish extremely difficult to identify. Like other types of anglerfish, frogfish use their first dorsal spine, which is topped with a special lure called an esca, to attract prey.
In many ways, frogfish more closely resemble their amphibian namesakes than their fellow sea creatures. They have short, stocky bodies with pectoral fins that could easily be mistaken for legs. Although some species may swim or fire jets of water from their mouths or gills, the most common form of locomotion is to use the leg-like pectoral fins to pull themselves along the sea floor. To onlookers, the fish appears to be walking with a gait much like a frog.
All species in the Antennariidae family are carnivores, feeding mostly on small fish and the occasional shrimp or crab. They hold perfectly still and use their specialized camouflage and esca lures, which may look like a worm or small crustacean, to attract prey. Once a victim is in range, the frogfish expands its mouth and strikes with incredible speed, swallowing its prey whole. It’s one of the fastest attacks of any fish, and can take as little as six-thousandths of one second.
Some species of frogfish are sought after as pets, but their feeding habits can make them difficult to maintain. They generally must be kept isolated, as they have no qualms about devouring any tank mates, even other members of the same species. Conversely, some species are camouflaged so well that other fish may mistake them for coral or seaweed, and may occasionally bite at the frogfish’s appendages in search of food.