Bathypterois grallator: Difference between revisions

Tripod fish
Conservation status
Template:StatusUnknown
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Aulopiformes
Family:	Ipnopidae
Genus:	Bathypterois
Species:	A. grallator
Binomial name
Bathypterois grallator (Goode & Bean, 1886)

The tripod fish, Bathypterois grallator, is an unusual bathypelagic (deep sea) fish. The tripod fish is named for the long extensions of its pelvic and lower caudal fins, on which it stands on the sea floor.

Tripod fish are relatively small, the largest known specimen having measured only 37 cm (14.5 in); however the three elongated fins of the tripod fish may extend to nearly one meter (3 ft 3 in) in length. The fish is slender, deeper than it is wide and with very small eyes that probably are not useful at the depths at which the fish lives. Tripod fish are very sensitive to the vibrations of other animals in the water. In addition to its tripods, the fish also has unusually large pectoral fins. Tripod fish have been found at depths of anywhere from 900m to 3500m (2950-11500 ft), and are distributed in all oceans in the equatorial regions.

The tripod fish is a relatively sedentary fish. It spends much of its adult life standing on the ocean bottom on its fins. The fish stands facing the prevailing current, and hunts by extending its unusually long pectoral fins into the current and waiting for the small crustaceans on which it feeds to simply bump into its fins. The fish grasps its prey in the pectoral fins and directs it toward its mouth.

The extensions of the pelvic and caudal fins are stiff enough for the fish to stand on them for (presumably) extended periods of time. However, deep sea researchers have succeeded in surprising the fish enough to make it swim; when it swims, the tripods seem to be quite flexible.

All tripod fish exhibit both male and female sex organs. While this trait (hermaphroditism) is not uncommon in other animals of the deep sea, the tripod fish is unusual in that the male and female organs reach maturity at the same time, thus allowing the tripod fish to fertilize its own eggs. It is supposed that tripod fish may be so sparsely distributed through the oceans that one fish may not be able to find another to mate when the time comes; thus as a last resort a single tripod fish could still reproduce, spawning young with identical genetic material as the parent.

The tripod fish is closely related to the smaller spiderfish (Bathypterois longifilis), which is similar in appearance and habits but smaller and with much shorter fin extensions; the two species are often found standing very near to one another on the ocean floor.

Very little is known about the life cycle of the tripod fish. The habits of the young of the species are virtually unknown. It is estimated that the species has very low resilience, and based on its sexual habits the total population and genetic variance of the tripod fish are both assumed to be small.

• Froese, Rainer; Pauly, Daniel (eds.). "Bathypterois grallator". FishBase. January 2006 version.

• Tripod fish photo, Monterey Bay Aquarium Research Institute