As its name implies, this mudfish species is restricted to the Canterbury region. This is the best feature for distinguishing it from the other mudfish, but the presence of pelvic fins on the Canterbury mudfish is also a unique feature of the mainland mudfish species. The Canterbury mudfish can be distinguished from other members of the Galaxiidae family by the presence of fewer rays in the pelvic fins (4 or 5 rays for Canterbury mudfish compared to 7 in the other galaxids). They also have comparatively small eyes.
The Canterbury mudfish is found from just north of Christchurch down the east coast to the Waitaki River. It has never been found south of there. It occupies weedy springs, drains, and irrigation races at low to mid altitudes across the plains and it does not usually co-exist with other fish species, probably because they frequent habitats that are subject to drying up in summer. Like the other mudfish species, it can aestivate when its habitat dries up and it remains buried in its hole in the mud until the water returns.
Canterbury mudfish lead a precarious existence and are considered to be a rare species. The development and drainage of swampy lands and subsequent lowering of the water table have probably contributed to their decline by reducing and fragmenting their habitat. Recently, a release of Canterbury mudfish occurred in a protected wetland near Willowby south of Ashburton, where it is hoped they will survive and reproduce. The establishment of similar populations in other protected wetlands is also desirable if we are to ensure that this unique New Zealand fish does not disappear.