A group of tuna is called a leash, an old term traditionally used for a small number of fish, often around three, caught or gathered together. “Leash” has historical roots in hunting and fishing vocabulary, where it referred generally to a set of three animals, whether hounds, foxes, or fish pulled from the water together.

Tuna themselves are powerful, fast-swimming predators built for speed and endurance, capable of crossing entire ocean basins and diving to remarkable depths in search of prey like squid, mackerel, and smaller schooling fish. Unlike many collective nouns that describe natural social behavior, “leash” is more of a fisherman’s term, tied to the practical act of catching and hauling in tuna rather than describing how the fish organize themselves in the wild.

In their natural habitat, tuna are more commonly described using terms like a school or a float, both reflecting the loosely coordinated groups these fast-moving predators form while hunting across open ocean.