Notoclinops yaldwyni
A tiny reef fish logged at 23 North Island sites, cool water 13.8 to 18.9 C, uncommon but findable year-round if you look close.
A finger-nail sized fish, around 4 cm, that perches motionless on rock and sponge rather than swimming in open water. Look for a slim, slightly humped body held at an angle, propped on its pelvic fins, with the three separate dorsal fins that give all triplefins their name. Colour runs from pale orange to reddish-brown, often with faint mottling, which makes it blend into the encrusted reef surfaces it sits on.
Expect to find it perched still on rock faces, ledges or sponge-covered surfaces rather than cruising the water column, which is typical triplefin behaviour. It tends to hold its ground at close range, letting divers get near before darting a short distance to another perch. Most sightings are logged as uncommon, so it rewards divers who slow down and scan small reef structure rather than mid-water.
Triplefins like this one lack a swim bladder, which is why they sit propped on the substrate instead of hovering, and why patient, close-range looking is the only reliable way to spot them.
There is not enough seasonal data to point to a particular month, so treat it as a year-round resident on North Island reefs. Observed water temperatures range from 13.8 to 18.9 C, spanning cooler and warmer parts of the local dive season, so it is not tied to a narrow warm-water window.
Reef neighbours a diver could mistake it for. Use the identification notes above to tell them apart.
Logged exclusively on New Zealand's North Island so far, with sightings spread across 23 sites there, this is currently a North Island specialty rather than a fish you will find elsewhere. No other country appears in the data, so North Island reef and rocky-shore dives are the place to look.
Mapping where Yaldwyn's Triplefin is logged…
All logged sightings so far come from New Zealand's North Island, where it has been recorded across a good spread of dive sites. It has not been documented diving elsewhere, so North Island reef sites are the reliable bet.
There is no clear seasonal pattern in the sighting data, so it appears to be a year-round resident. It has been logged across a range of water temperatures from 13.8 to 18.9 C, so cooler and milder months both work.
Look for a tiny, roughly 4 cm fish perched still on rock or sponge rather than swimming freely, with a slim body and three distinct dorsal fins. Its colour is typically pale orange to reddish-brown with subtle mottling that blends into the reef.
They are small, topping out around 4 cm, which is typical for triplefins and part of why they are easy to overlook on a dive.
No, they pose no danger to divers. They are small, reef-bound fish that hold still or dart short distances when approached.
Like other triplefins, it has no swim bladder, so instead of hovering in the water it rests propped on its pelvic fins against rock or sponge surfaces. This perching habit is the main giveaway when scanning a reef for it.
Site and sighting data is aggregated from diver logs, iNaturalist and GBIF. For taxonomy and conservation status:
Klipfish
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