The New Zealand native galaxiid species inanga (Galaxias maculatus), banded kokopu (Galaxias fasciatus) and black mudfish (Neochanna diversus) are closely related, but exhibit different habitat preferences, with distinct oxygen regimes. Inanga prefer lowland open rivers and lakes, while banded kokopu usually live in heavily shaded pools of small tributaries and black mudfish primarily inhabit lowland swamps and wetlands. The capacity of each species to detect and respond to progressive, escapable hypoxia was studied using a choice chamber. Of the three species inanga were the most sensitive, actively avoiding mild hypoxic conditions (< 5.9 mg L-1), while the avoidance threshold of banded kokopu was lower at < 2.5 mg L-1 and black mudfish demonstrated no avoidance of hypoxic water. In addition, species displayed specific behavioural responses to hypoxia. The frequency with which inanga switched between hypoxic and normoxic areas increased with more severe hypoxia. Banded kokopu increased the frequency of surface respiration and swimming speed, improving oxygen uptake through increased ventilation of oxygen-rich near-surface water. Black mudfish displayed no obvious change in behaviour to hypoxic conditions, indicating a pronounced hypoxia tolerance. These findings demonstrate species-specific hypoxia sensitivities and distinct behavioural strategies towards hypoxic environments.