Blenniella gibbifrons
An 8cm reef fish most logged in Hawaii, uncommon but findable on shallow rocky reef in warm 24-29C water year-round.
A tiny fish at just 8 cm, mottled in browns and greys that blend against algae-covered rock, with a distinctly humped, blocky forehead profile that gives it its name. It perches propped on its pectoral fins rather than swimming freely, and its eyes sit high on that raised head, giving it a slightly bug-eyed look when you get close. Look for it resting motionless on rubble or rock rather than in open water.
Divers most often find it perched still on rock or rubble rather than cruising the reef, using those forward-set pectoral fins to prop itself up like a little tripod. It tends to hold its ground when a diver approaches slowly, darting only a short distance to the next patch of rock if disturbed. Most sightings come from shallow, current-swept rocky reef where algae growth gives it both cover and food.
Like other combtooth blennies, it grazes algae directly off rock surfaces with comb-like teeth, making it one of the reef's quieter algae groomers rather than a hunter.
No clear seasonal pattern shows up in the sighting data, and it sits comfortably in water from about 23.6 to 29.3 C, so Hawaii's reefs stay within that range through the year. Treat it as a year-round find rather than something tied to a particular month.
Reef neighbours a diver could mistake it for. Use the identification notes above to tell them apart.
This one is very much a Hawaii speciality among logged sightings, with every recorded site so far in Hawaiian waters. Within Hawaii it turns up across a broad spread of reef and rocky-shore dive sites rather than being pinned to one or two famous spots.
Mapping where Humpheaded Blenny is logged…
Sightings are concentrated in Hawaii, where it has been logged across a wide range of dive sites. It has not been reported in meaningful numbers outside Hawaiian waters so far.
There is no strong seasonal pattern in the sighting data, so it is considered a year-round find. It lives comfortably in water between roughly 24 and 29 C, which covers Hawaii's reefs for most of the year.
Look for a small, 8 cm mottled brown fish with a distinctly bumpy, raised forehead perched motionless on rock or rubble. It rests propped on its fins rather than swimming in open water, which helps separate it from more active reef fish nearby.
They stay small, typically around 8 cm long, making them easy to overlook against textured rock and algae.
No. They are harmless, tiny reef fish that hold still or dart short distances when approached, posing no risk to divers.
Its comb-like teeth let it graze algae straight off rock surfaces, a feeding style shared across combtooth blennies that makes it a small but steady algae-grazer on the reef.
Site and sighting data is aggregated from diver logs, iNaturalist and GBIF. For taxonomy and conservation status:
Ophioblennius atlanticus
Klipfish
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