The Northland mudfish is a newly discovered member of the mudfish genus. As its name implies, it is only found in Northland and only then from a fairly restricted area near Kerikeri. It can be distinguished from the other mudfish species by counting the caudal fin rays; the Northland mudfish has only 13 or fewer rays whereas the other mudfish usually have 14 or more. The body also has a distinct reddish tinge, particularly on the fins. The largest Northland mudfish on record is 134 mm long, and adult specimens regularly exceed 100 mm in length.
Little is known about the life cycle of the Northland mudfish, although it is undoubtedly similar to that of the other mudfish species. The distribution pattern of the black mudfish overlaps that of the Northland mudfish, but the two species have never been caught together.
The conservation status of the Northland mudfish is uncertain. The largest population occurs in a protected conservation area, but already a separate, smaller population has disappeared in conjunction with deteriorating water quality at the location.