Here we investigate how aquatic hypoxia affects the SDA response, in terms of peak metabolic rate (MO2peak) and size of the SDA, and how the postprandial rise in metabolism influences the partitioning of oxygen uptake from air and water. We hypothesised that the SDA response is accomplished by an increase in the relative importance of aerial respiration (MO2air), and that aquatic hypoxia increases the reliance on MO2air. Since these fish have reduced gills and are considered to be obligate air-breathers, we hypothesised that hypoxia would not affect the total SDA, duration, or MO2peak. The ventilatory response to hypoxia was also characterised in fasted fish, and we expected aquatic ventilation to decrease with gradual hypoxia, and that air-breathing frequency would increase gradually with decreasing oxygen.