Knowledge of reproductive strategies of threatened fishes is critical to the management of their populations, especially attributes that can enhance breeding success. Approximately 20% of teleosts exhibit ‘parental care’, a behaviour that enhances the survival and development of offspring; however, this strategy has not been documented in galaxiids, which are dominant in temperate inland waters of several land masses in the Southern Hemisphere.

Arthurs Lake, Great Lake and Lake Augusta are home to all four species of Paragalaxias, which is an endemic genera to central Tasmania, Australia.

During a five-year study, snorkel-based observations and in situ underwater camera equipment were used to examine spawning sites and parental behaviour of all four Paragalaxias species (Paragalaxias dissimilis, P. eleotroides, P. julianus and P. mesotes). These fishes deposit discrete broods of eggs (<400 eggs) on the undersides of cobbles and boulders in shallow lake margins (mean depth ~0.6 m). Interestingly, all four species appear to exhibit a form of parental care, with egg defence, egg care (fanning and cleaning of broods) and possibly filial cannibalism (a behaviour used to enhance the survival and longevity of egg guarding parents) being observed.

Harem polygyny appears to also exist with spawning sites commonly being shared. This may be energetically advantageous for adults. Aggregations of broods on individual rocks could also reduce the impact of cannibalism on distinct broods. To date, field observations have shown that the reproductive strategy of Paragalaxias species is complex and that these fishes may be suitable candidates for more detailed behavioural studies.