Shortjaw kōkopu
A scaleless New Zealand galaxiid fish.
The shortjaw kōkopu is a large, scaleless ray-finned fish found only in New Zealand. It lives in forested streams and migrates to the sea as a fry before returning to fresh water to mature.
- Endemic to New Zealand streams
- Scaleless body structure
- Amphidromous life cycle
- Grows up to 350 mm long
- Detected via environmental DNA
What it is
This species is a ray-finned fish belonging to the galaxiid family. It lacks scales and can grow quite large for its group. Adults typically measure between 150 and 200 millimetres, though some reach 350 millimetres. The fish is endemic to New Zealand, meaning it is found nowhere else in the world. It prefers stable pools within streams that cascade over boulders and are shaded by forest canopy.
Where it lives
The shortjaw kōkopu inhabits specific microhabitats within New Zealand waterways. These areas feature large particles on the stream bed and provide ample shelter compared to surrounding spots. In 2023, environmental DNA testing revealed a new population in the Kopuawhara catchment, north of the Māhia Peninsula in Hawkes Bay. This detection expanded the known distribution of the species within the country.
How it lives
These fish display distinct daily movement patterns. At night, they stay in calm pool areas. During daylight hours, they move into zones with large substrates and more turbulent water surfaces. They utilise both flow channels and pool habitats throughout the day. This behaviour allows them to balance safety with feeding opportunities in their complex stream environments.
Breeding and life cycle
The species follows an amphidromous life cycle. After hatching in fresh water, the fry migrate to the sea. They spend part of their early development in marine environments. As juveniles, they return to freshwater streams. There, they grow into adults in the stable, forested pools that characterise their preferred habitat.
Fish and people
The shortjaw kōkopu has been featured in public media, including a discussion on RNZ Critter of the Week in May 2020. It is recognised as a native freshwater galaxiid fish in New Zealand. Resources such as TerraNature have documented its characteristics for public education and awareness regarding native species.
Questions people ask about Shortjaw kōkopu
Where does the shortjaw kōkopu live?
It is endemic to New Zealand. It inhabits stable pools in cascading, boulder-strewn streams that have forest cover. Recent findings place it in the Kopuawhara catchment.
How big does this fish get?
Adults commonly reach lengths of 150 to 200 millimetres. The maximum recorded total length for the species is 350 millimetres, which is about 14 inches.
What is its life cycle?
The fish is amphidromous. Fry hatch in fresh water, migrate to the sea, and return as juveniles to grow into adults in freshwater streams.
Good reading and sources
- Shortjaw kōkopu on WikipediaEncyclopedia
- More photos on Wikimedia CommonsPhotos
- Wikidata recordOpen data
The facts on this page come from the Wikipedia article "Shortjaw kōkopu", written by its contributors and used under the CC BY-SA 4.0 licence, and from its Wikidata record (CC0). EveryFish rewrote the text in its own words, with AI assistance, and compares every page with the article to make sure no passage is copied. It may be reused under the same CC BY-SA 4.0 licence with a link back.
It may contain mistakes, and figures change over time. Nothing here is investment or buying advice. If something is wrong, tell us. Last refreshed 2026-11-15.
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