Tripodfish

Lore & Background

Bathypterois grallator is a simultaneous hermaphrodite, where each individual has both male and female reproductive organs. It mates by releasing both sperm and eggs into the water, which can be externally fertilized by another B. grallator. In the event one fish cannot find a mate, it can also self-fertilize, which increases the likelihood of reproduction in the sparsely populated abyssal plain. The tripod fish has been listed as least concern by the IUCN as of May 2013 with no specific major threats to the species. However, the tripod fish's habitat is known to be affected by human activity, such as deep-sea mining, drilling, and plastic waste.

In Their Own Story

The tripod fish has been found on the continental slope and abyssal plain in the Atlantic, Pacific, and Indian oceans from 40°N to 40°S, as well as near coastlines in Africa, North America, Central America, and Madagascar. It is a wide-ranging eurybathic and eurythermal fish found from 878 to 4,720 m (2,881 to 15,486 ft) in depth and in water temperatures ranging from 2.7 to 13.5 degrees Celsius. B. grallator does not appear to have a preferred habitat, remaining consistently widespread through most oceans in the mid-latitudes and sharing habitats with other tripod fish, such as Bathypterois longifilis which it has been observed standing in close proximity to.

Reader's Guide

The tripod fish is a subcarangiform swimmer, using a combination of its fins, tail, and body to move. Because its adaptations are almost entirely tailored to sitting still, B. grallator's movements are exaggerated and inefficient, and it is an overall poor swimmer. Its style of locomotion alternates between swimming and resting on the seafloor using its fins, using a unique bathypteroiform style of movement that is unique to the genus. When swimming, its pectoral, dorsal, and anal fins are held directly away from the body and are used for stabilization, while its elongated pelvic fins are held directly downward and perpendicular to its body. When feeding, it is often seen standing on the seafloor using these extensions, in a distinctive "tripod" configuration that gives the species its name. B. grallator's diet consists mostly of zooplankton and small animals in the water column, and it undergoes an ontogenetic shift as it grows larger. Specimens below 200mm in length are mostly recorded eating small invertebrates such as copepods, amphipods, and crustacean larvae, while larger fish also eat mysids. Above 240mm, the tripod fish's diet consists mostly of teleosts and decapods by weight, with approximately 78.7% of their diet consisting of teleosts.

Did You Know?

• B. grallator is the largest member of its genus, reaching total lengths of up to 43.4 cm (17.1 in).
• Its pectoral and caudal fin extensions can reach up to a meter in length, approximately three times the length of its body.
• Tripod fish are simultaneous hermaphrodites and can self-fertilize if no mate is found.
• Specimens above 240mm have a diet consisting of approximately 78.7% teleosts by weight.
• The species has been listed as least concern by the IUCN as of May 2013.