Oneknife Unicornfish

Care Summary

The Oneknife is distinguished from every other Naso species by having a single fixed caudal spine rather than the paired peduncle plates that define the genus, which makes it immediately identifiable to anyone who knows what to look for. It is a torpedo-shaped open-water swimmer that never quite settles in a home aquarium the way a Naso tang does; it stays restless and needs serious horizontal swimming space. The species is rarely offered in the trade, so when one does appear, it typically goes to serious collectors with the infrastructure to support it properly. For most hobbyists, one of the more manageable Naso species is the better long-term choice.