Tripod fish (Bathypterois grallator)
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.
The dull brown tripod fish lives on the ocean floor. The pelvic fins are very long, about half the length of these fish which can grow to 29 cm. The pelvic fins and long tail help the tripod fish skim along the ocean floor. Tripod fish eat zooplankton. Threads on the fins sense the zooplankton in the water when they brush into the fins.