Hypsoblennius gilberti
Small, uncommon blenny found tucked into rocky reef holes along California, present year-round in 17-29C water.
A small, stocky blenny reaching around 11cm, usually seen with just its head poking out of a rock crevice or empty shell. Body colour is mottled brown to olive, blending closely with the surrounding rock and algae, and the head carries small fleshy tufts (cirri) above the eyes. Look for the eyes set high on a blunt head and the way it perches motionless rather than swimming freely across open reef.
Expect to find it wedged into a crevice, empty barnacle shell, or small hole in the rock, with just the head and eyes visible watching the reef. It is not a fish that cruises open water: divers typically spot one by slowing down and scanning rocky nooks rather than by seeing it swim past. When approached closely it tends to hold still or retreat deeper into its hole rather than bolt across open ground.
Its small head cirri and habit of sitting head-out in a single hole for extended periods make it one of the easier blennies to photograph once you spot it, since it rarely darts off the way open-water fish do.
Sightings do not show a clear seasonal pattern, so treat this as a year-round species on the sites where it occurs. Its observed range of 17.1 to 28.8C spans the swings of California's coastal water temperature, which likely explains why it shows up across the calendar rather than in a narrow window.
Reef neighbours a diver could mistake it for. Use the identification notes above to tell them apart.
Every logged sighting for this species comes from California, USA, making it a specifically Californian find rather than something spread across warm-water dive destinations. Within California it turns up on rocky reef and cobble sites, so divers exploring the state's kelp and rock reefs have the best shot at spotting one.
Mapping where Notchbrow Blenny is logged…
All recorded sightings are from California, USA, on rocky reef sites along the coast. It has not been logged as a common find outside California.
There is no strong seasonal pattern in the sightings, so it can be found year-round at its California sites. Its comfort range of roughly 17 to 29C covers most of the region's water temperature swings.
Look for a small, mottled brown fish around 11cm long, poking its head out of a rock crevice or empty shell with tiny fleshy tufts above the eyes. It sits still rather than swimming in open water, which is often the biggest giveaway.
They reach about 11cm in length, making them one of the smaller reef fish divers might photograph on a California dive.
No, they pose no danger to divers. They are small, hole-dwelling fish that retreat rather than confront anything approaching.
It is logged as uncommon at most of its known sites and rare at a couple of others, so it is not a guaranteed sighting even where it occurs. Slowing down to check crevices improves your odds.
Site and sighting data is aggregated from diver logs, iNaturalist and GBIF. For taxonomy and conservation status:
Klipfish
1,860 sites
