In 2018 a new spawning site was discovered in a tributary of York Stream, Nelson, where fish habitat and passage restoration has been carried out as part of Project Maitai.

Banded kōkopu are diadromous, spending the first 3–4 months of life at sea, before migrating back to freshwater as whitebait of 40–45 mm (1.6–1.8 in) in length.

[7][8] As the flood recedes the eggs are left to develop out of the water; the high humidity provided by the vegetation keeps them moist.

[7] After three to four weeks the embryos are fully developed and require a second flood to stimulate them to hatch, and the larvae are carried to sea on the floodwaters.

This suggests they have the ability to discriminate species-specific pheromones during their migratory phase, which alerts juveniles to suitable habitat based on the presence of adults.

Banded kōkopu are largely nocturnal, and may be easily and unobtrusively observed night, ideally using red light.