Description:
<jats:p>Frequency of aerial respiration in <jats:italic>Ctenopoma muriei</jats:italic> increased as dissolved oxygen (DO) decreased; breathing behaviour was spatially synchronous, and there was no difference in air‐breathing frequency between populations from a high‐ and low‐DO site. Although <jats:italic>C. muriei</jats:italic> survived without access to the surface, its loss of buoyancy and equilibrium under these conditions suggested that it is a functionally obligatory air breather.</jats:p>