The maximum size of the black tongue can grow to 75cm. Most of the black tongues live in the clear lagoons and the water depth of the outer reef slope between 6-150 meters. They are usually group activities. Cranes usually swim together in large groups on reefs and mid-surface waters.

The adult black tongue hanging has a blue-gray back and a pale yellow abdomen , The gill membrane of the fish body is dark brown, and the tongue is black. Under normal circumstances, there are no markings on the side of the black tongue. Black horns mainly eat zooplankton, such as crab larvae, arrow worms and planktonic tunicates, but sometimes they also eat red thread algae.