Fangtooth fishes (Anoplogaster cornuta, Anoplogaster brachycera) are a genus of deep sea beryciform fishes, classified as being in the family Anoplogastridae (unarmed stomach). The common names for the two currently recognized species are: the common fangtooth, and the shorthorn fangtooth.

The two species of fangtooths possess a circumglobal distribution, and are found mostly in tropical and cold-temperate waters. The genus that contains the two species is the only one in the family, and there are no known close relatives.

The fangtooths are named thusly, obviously, owing to their huge fang-like teeth — and overall strange appearance. That said, though, the species are more or less harmless as far as threats to humans go. They don’t really get any larger than 7-inches long, and mostly just eat small fishes.

Fangtooths actually possess the largest teeth (proportionate to body size) of any extant fish species in the world. They are so big that the species is apparently not ever able to completely close their mouth. To aid in the closing of their mouths, though, there are recessed pockets in the upper part of the mouth, on either side of brain — which apparently helps some, but not enough to allow for full closure.

The fangtooths, as alluded to before, are amongst the deepest-living fish currently in existence — and are regularly found at depths of over 6000 feet below the water’s surface, and sometimes as deep as 16000+ feet below the surface. Older individuals apparently tend to often be found at greater depths than juveniles.

On the subject of juveniles — they are quite interesting looking. To put it politely. Ahem.

Here’s some more information on the fangtooth:

The head is small with a large jaw and appears haggard, riddled with mucous cavities delineated by serrated edges and covered by a thin skin. As compensation for reduced eyes, the lateral line is well-developed and appears as an open groove along the flanks.

They may undergo diel migrations as is common with many deep-sea fish: by day these fish remain in the gloomy depths and towards evening they rise to the upper layers of the water column to feed by starlight, returning to deep water by daybreak. Fangtooths may form small schools or go alone. They are thought to use contact chemoreception to find prey, relying on luck to bump into something edible.

Based on the smaller teeth and more developed gill-rakers of the juveniles it’s thought that they feed primarily on zooplankton filtered from the water — whereas the larger, older individuals feed on other fish and on deep sea squid

Despite their fearsome appearance, fangtooths are thought to be regularly preyed upon by other well-known deep-sea fish — larger, faster ones though — such as tuna, marlin, sharks, etc.

Interestingly, in contrast to most other nearly exclusively deep sea fish, fangtooths can actually survive being brought to the surface (in contrast to fish that distort, and “explode”, such as blobfish). “They have been kept alive for months in aquariums despite conditions which are significantly different from their usual deep-sea habitat.”

Fangtooths have planktonic larvae and are assumed to not be egg guarders; spawning frequency and time are not certain, but some activity has been reported from June–August. The juveniles of common fangtooths begin to assume adult form from about 8 cm (3 in) in length, at which time they begin to descend into deeper water. Onset of maturity is not known, but common fangtooths are known to be mature at 16 cm (6.3 in). They are probably slow-growing, as are most deep-sea fish.

Those wondering what some of fangtooth’s competitors and neighbours down at the bottom of the ocean look like, can find some of that information here: Deep Sea Fish — Black Dragonfish, Long-Nosed Chimaera, Blobfish, Hatchet Fish, Giant Oarfish, Barreleye Fish, Sloane’s Viperfish, Etc

Image Credits: Public Domain; Screen Capture; MBARI