Fine structure of the respiratory surfaces of an air-breathing fish, the climbing perch Anabas testudineus (Bloch).

Abstract

THREE principal surfaces are used for respiratory gas exchange in the anabantoid fish: (1) secondary lamellae of the gills; (2) plates of the labyrinthine organs lying dorsal to the gills; and (3) the respiratory membrane lining the suprabranchial cavity which contains the labyrinthine organs. Secondary gill lamellae are the sites of exchange between the blood and water, but the labyrinthine plates and respiratory membrane function during exchange between blood and the air contained within the suprabranchial chamber.