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Today on Animal Fact Files we’re discussing batfishes. There are a few different fish groups with this common name. There are eagle rays known as batfish, freshwater batfish, and fish commonly kept in home aquariums known as batfish, but these groups all have other common names. The batfishes described in this video are anglerfish. There are approximately 90 described living batfish species, and they live along the bottom of the ocean. Like other anglerfish, batfishes use a fleshy lure located above their mouth to draw prey in. This lure, called an esca, does not give off light. Instead, they use visual and chemical signals to draw prey in. Bobbing the lure up and down can catch a wandering crustacean's gaze and a chemical pheromone may entice a roving fish. Batfishes can retract their lure when not in use! 

These fish look squished. They have flattened bodies and some highly adapted, muscular fins. Batfishes aren't good swimmers. In fact, one author described them as similar to a "drowning cow" while swimming. Instead of swimming, batfish walk along the bottom of the ocean using their leg-like fins for movement. They're slow moving, but they don't need to move fast when all their prey is lured to them. Batfishes eat fish, crustaceans and other invertebrates like worms. Their mouths are nearly horizontal on their face, and they often have thick lips like this red lipped batfish. The bright lip colors are hypothesized to be used for mating as they’re often seen in reproductive aged males!

Batfish are not only benthic creatures, most species are also deep sea dwellers. On average, these fish live from five hundred to over five thousand feet (150-1,500m) below the waves, but some live double that depth! They frequent continental shelves and slopes, and they're found in tropical and temperate seas around the world. They wedge themselves against a rock or coral formation while resting, usually during the day. Some hide themselves under sand while luring in prey but others hold their body in a striking position. There are, of course, always the outliers. Some species aren't as squished looking as the others. These box-shaped batfish spend some of their time above the sea floor in search of food. Some batfish species live closer to the coast, sometimes entering brackish water estuaries; these species are most commonly seen in the western hemisphere.

On average, batfishes are about two to eight inches (5-20cm) long, but they can double that at max size. Some species, especially deep water species, have pointy noses, and many come with lumps and bumps across their body to help them blend in with their environment. Batfish use camouflage to hide from potential predators and often bury themselves in sand when threatened. Sea lions and sharks have been known to eat them, and most batfish caught and brought into aquariums are full of parasitic worms like nematodes and leeches! People catch them as bycatch in fishing operations, but rarely eat them.

There is very little known about batfish reproduction. They have floating egg rafts containing a few thousand eggs, each with an oil drop inside for buoyancy. Batfish larvae have been observed in the open ocean, still globular and not settled to the sea floor. In captivity, certain species have survived longer than a decade!

So why are they called batfishes? We actually don't know! We looked everywhere for an answer, but couldn't find anything concrete. Our guess is that these fish look like little bats crawling along the seafloor when viewed at the right angle. What do you think?

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