Tripod fish is a common name for several different species of fish, consisting of the Ipnopidae, a family found worldwide in deep seas, the Bathypterois grallator, the most renowned species of tripod and the Triacanthidae.
Tripod fish are a temperate and tropical ocean fish, with colour ranges from a bronze to a pale colour, with grey on its head, underside and lower back. It's a deep sea fish living in the Pacific and Atlantic oceans, on the ocean floor at depths between 900 and 4,700 meters. The fish can only survive in saltwater.
The unusual anatomy of this fish consists of modified pelvic and caudal fins (or tail fins), that are elongated at the tips and are called rays, or elements. The fish's rays are rigid whilst it perches on the ocean bed, but have been observed in scientific deep sea studies to be flexible when the fish swims away, if it is disturbed, or just moving location.
The tripod is a fairly small fish, measuring between 30-37cm on average. Taking into account its fins though, it can extend in length to just under one meter. The fish is slim and tall, rather than bulky in girth. Since it lives in constant darkness in the deep sea, the eyes of the tripod have virtually disappeared and are ineffective for seeing. Instead, the tripod uses its senses, which operate through the long and feathery extended pectoral fins, to pick up vibrations through the water. The vibrations signal that prey and a mealtime are approaching. The fish then hold out its pectoral fins above its head like antenna, to direct food towards the a very large gaping mouth.
Tripods will eat small planktonic crustaceans, zooplankton, and any tiny organism in the ocean that come their way. Whilst facing towards the direction of the moving current the fish further increases the chances of prey being swept along in its direction. This is how the tripod spends its time, standing around on its unusually-developed tripod anatomy, waiting for food to arrive, or for a mate to come along.
Another interesting feature about the anatomy of the tripod fish is that they are hermaphrodites, having both male and female sex organs. While this is not uncommon amongst deep sea creatures, the tripod fish is unusual in that both its male and female sex organs reach sexual maturity at the same time. Therefore, the fish is capable of fertilising its own eggs. This is a useful feature of its anatomy, when harsh and desolate conditions in the environment it lives in, mean that Tripod fish may not come into contact with a mate for long periods of time, if at all, during their variable lifespan of somewhere usually between three to five years.