Tetrabrachiidae

Tetrabrachiinae, or the four-armed frogfishes or doublefin frogfishes, is a small subfamily of marine ray-finned fishes belonging to the family Antennariidae in the order Lophiiformes, the anglerfishes.'''' These fishes are found in relatively shallow waters of the eastern Indian Ocean and western Pacific Ocean.

==Taxonomy== Tetrabrachiidae was first proposed as a subfamily, the Tetrabrachiinae, of the family Antennariidae in 1912 by the English ichthyologist Charles Tate Regan with only a single genus included, Tetrabrachium, a monospecific genus which had been proposed by Albert Günther in 1880. In 2009 a second monospecific genus, Dibrachichthys, was added to the family when it was described by Theodore Wells Pietsch III, Jeffery W. Johnson and Rachel J. Arnold. Although upgraded to its own family previously, it was again subsumed to a subfamily of the Antennariidae in 2025. The Tetrabrachiidae is classified within the suborder Antennarioidei within the order Lophiiformes, the anglerfishes. This family is regarded, with its sister taxon the Antennariidae, as the most derived clade within the suborder Antennarioidei.