Pleurosicya elongata
A 3cm goby found only on sponges around Luzon, Philippines, in warm 25-29C water. Here's how to spot one on the reef.
At about 3cm long, this is a needle-thin goby with a near-transparent to pale body that lets it blend almost completely into the sponge tissue it sits on. Look for a slender, elongated profile compared to other sponge-dwelling gobies, with faint mottling rather than bold bars or spots. It rests motionless on the sponge surface, so the giveaway is often the shape and stillness rather than colour.
This goby sits tight against its host sponge, barely moving except for small sideways shuffles as it feeds on passing plankton and detritus caught in the sponge's currents. It is unbothered by divers at typical viewing distance but will duck to the far side of the sponge if you get a torch or lens too close. Most sightings are of single individuals on a specific sponge rather than groups scattered across the reef.
Like other Pleurosicya gobies, it lives its whole adult life attached to a single sponge host, feeding on the mucus and plankton the sponge filters, which makes finding the right sponge more important than covering more reef.
There is no detected seasonal pattern, and with water temperatures logged between 25.4 and 28.9C, conditions stay suitable year-round on Luzon's reefs. Dive any month and focus your search time on sponges rather than the calendar.
Every logged sighting so far comes from the Philippines, with Luzon standing out as the region where divers most reliably find it. Search sponge-covered reef structures on Luzon dive sites rather than open coral for the best chance of a sighting.
Mapping where Slender Spongegoby is logged…
All recorded sightings are from the Philippines, concentrated in Luzon. Look on sponge-covered structures at Luzon dive sites rather than expecting it on open coral reef.
There's no clear seasonal pattern in the data, and water stays in a comfortable 25.4 to 28.9C range year-round in its habitat. Any month is a reasonable time to look.
It's a tiny, slender, near-transparent goby about 3cm long sitting motionless on a sponge surface. Its slim body shape and pale, mottled colouring are the main clues, since it lacks bold stripes or spots.
They stay tiny, typically around 3cm in length, which is part of why they're logged as uncommon even at sites where they occur.
Yes, like other members of its genus it attaches to a single host sponge and rarely strays far, feeding on plankton and mucus the sponge filters from the water.
Site and sighting data is aggregated from diver logs, iNaturalist and GBIF. For taxonomy and conservation status:
Slender Goby
803 sites
