Trimma striatum
A 2cm goby logged in Palau's Koror & Malakal and Sulawesi reefs at 26-28.5C, worth a slow look on any macro dive.
A translucent, pin-sized goby barely 2cm long, marked with fine reddish longitudinal stripes running along a mostly see-through body. It perches motionless on coral rubble or bare reef substrate rather than swimming in open water, propped up on its pelvic fins in typical goby fashion. The stripes and tiny scale are the two things to check before assuming it is just another reef goby.
Expect to find it sitting still on rubble or low reef structure rather than darting about, which is typical for small Trimma gobies that rely on staying inconspicuous. Divers report it as uncommon even at the sites where it turns up, so it takes a patient, close-focus search rather than a casual swim-by. It is not shy in the sense of fleeing, more that its size and stillness make it easy to swim straight past.
Like other Trimma gobies, this species is thought to be a simultaneous hermaphrodite capable of functioning as either sex, an adaptation useful for a fish this small and scattered across the reef to still find a mate.
There is not enough seasonal data to point to a particular window, and its comfort range of roughly 26.4 to 28.5C matches warm tropical reef water year-round in Palau and Sulawesi, so any time of year is fair game.
Logged sightings cluster around Koror & Malakal in Palau, with a further record from Sulawesi in Indonesia, making Palau the more reliable bet for this species so far. Both regions offer the kind of coral rubble and reef nooks this goby favours, so a slow macro-focused dive in either spot gives you the best odds.
Mapping where Redlined Pygmy Goby is logged…
Sightings are most reliably reported around Koror & Malakal in Palau, with an additional record from Sulawesi in Indonesia. Palau currently offers the stronger chance of finding one.
There is no detected seasonal pattern for this species, and its preferred water temperature of roughly 26.4 to 28.5C is present year-round in its known range, so it can turn up on any dive regardless of season.
Look for a nearly transparent body under 2cm long with fine red stripes running lengthwise, perched still on coral rubble rather than swimming freely. Its small size means you need to slow down and scan the substrate closely.
They max out at around 2cm, making them one of the smallest gobies you might encounter on a reef and easy to overlook without a careful look at the substrate.
No, this tiny goby poses no risk to divers. It is far too small and inoffensive to be any kind of hazard underwater.
Site and sighting data is aggregated from diver logs, iNaturalist and GBIF. For taxonomy and conservation status:
Slender Goby
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