Simultaneous measurement of buccal water-pressure changes verified the presence of coughing manoeuvres on strip-chart recordings of bioelectric potentials associated with respiratory movements and sensed with non-contact electrodes from cannulated bluegills. Additional recordings, here called 'electrobranchiograms' (EBGs), showed that non-cannulated and well-acclimated bluegills normally display an arrhythmic respiratory pattern similar to Biot's breathing, in which pauses in breathing (apnea) characteristically alternate with groups of ventilating cycles. Three types of bluegill coughing manoeuvres were identified.