Periclimenes rathbunae
Tiny translucent shrimp living on anemones in Honduras's Bay Islands and Grand Cayman, 24.6-30.6C, year-round if you look close.
A small, near-transparent shrimp with faint white or purple markings along its body, easy to miss unless it's sitting on the pale tentacles of a host anemone. Its slender legs and long antennae give it away more than colour does, since the body itself is mostly see-through. Look closely at anemone crowns rather than scanning open reef, this is a macro find, not a mid-water sighting.
Divers find it parked on or near the tentacles of its host anemone, moving in short hops rather than swimming off across the reef. It doesn't flee when a light or camera comes close, which is part of why it's a favourite subject for macro photographers who take the time to search anemone clusters carefully.
Like many anemone shrimp, it likely relies on a coating that makes it unpalatable or unrecognisable to the host's stinging tentacles, letting it live safely among cells that would sting most other animals.
No clear seasonal pattern shows up in the sightings, and the water temperature range recorded, 24.6 to 30.6C, spans nearly the whole year on these reefs, so it's a fair bet in any month. Treat it as a year-round find rather than something tied to a particular season.
Reef neighbours a diver could mistake it for. Use the identification notes above to tell them apart.
Most reliably logged in Honduras's Bay Islands, which account for the bulk of sightings, with a smaller but steady presence around Grand Cayman in the Cayman Islands. Occasional records also come from the Willemstad and South Coast area of Curacao, so Caribbean anemone-covered reefs generally are worth checking.
Mapping where Shrimp is logged…
The Bay Islands of Honduras are the most consistent spot, with Grand Cayman in the Cayman Islands also a solid bet. Curacao's south coast has produced occasional sightings too.
There's no strong season in the sighting data, and the water stays warm enough (24.6 to 30.6C) for it to be present year-round. Any month on a Caribbean reef dive is worth a look.
Look for a small, mostly transparent shrimp with faint markings, sitting on an anemone rather than out in the open. Its see-through body and close association with a host are the main clues, since colour alone won't help much.
Exact size figures aren't well documented for this species, but like other Periclimenes anemone shrimp it stays small, easily overlooked without a close look at anemone tentacles.
No. It poses no threat to divers and is entirely reef-scale, more likely to be missed than to cause any concern.
It shelters directly on stinging anemone tentacles, a spot most reef animals avoid, likely protected by a mucus coating that stops the anemone's stinging cells from firing on it.
Site and sighting data is aggregated from diver logs, iNaturalist and GBIF. For taxonomy and conservation status:
Freshwater Shrimp
2,168 sites
