Cardiac and respiratory responses in the climbing perchAnabas testudineus

The heart rate ofAnabas is about 40 beats/min when breathing water and air. Tachycardia occurs as the fish takes an air breath and the rate declines as the breath holding continues but water breathing stops. Bradycardia is observed during this later phase. By the time the next air breath is taken, the heart rate has dropped to 15–30 beats/min. The heart rate of a fish breathing normoxic water but prevented from surfacing is about 42/min....