What is the longest bony fish?

The oarfish is the longest bony fish. The giant oarfish, Regalecus glesne, can reach roughly 7–8 metres, making it longer than any living bony fish regularly recognized by zoologists.

Oarfish belong to the family Regalecidae and have a remarkable ribbon-like body. Their long dorsal fin runs almost the entire length of the fish, while the first fin rays form a striking red crest above the head. The thin, silvery body and trailing fins have helped inspire old sea-serpent stories.

Despite their size, oarfish are rarely seen alive because they inhabit the open ocean, especially the upper mesopelagic zone. They move by undulating the dorsal fin and may hold their bodies vertically while feeding. They lack a swim bladder, unlike many other bony fish, and their gelatinous flesh is not highly valued as food.

The common mix-up is with the whale shark, which is much larger overall but is a cartilaginous shark, not a bony fish. “Longest bony fish” is therefore a different record from “largest fish.”