Athanas nitescens
Small, easy-to-miss shrimp turning up in cool water (9.8-15.8C) across Brittany's rocky dive sites, year-round.
A small, semi-translucent shrimp with a mottled brownish or greenish tint that helps it blend against rock and weed. Look for the arched, hood-like carapace over the head that gives it its name, and a slender body tucked close to crevices rather than swimming in the open. It rarely sits still in full view, so divers usually spot it by torchlight picking through algae and rubble.
Found tucked into rocky crevices, under stones, and among weed and rubble rather than out in open water, moving in short, cautious bursts when disturbed. It tends to stay close to cover and is easily overlooked among the debris and algae it resembles, so most divers find it while searching slowly with a torch rather than spotting it mid-water.
Its arched, hood-shaped carapace is the main giveaway among small crevice-dwelling shrimp in these cooler European waters, a useful shape cue when colour alone is hard to judge under torchlight.
Sightings show no clear seasonal pattern, and the observed temperature range of 9.8 to 15.8C spans much of the diving year in these cool Atlantic and Channel waters, so it is worth looking for at any time you're diving Brittany or the Channel Islands.
Reef neighbours a diver could mistake it for. Use the identification notes above to tell them apart.
Overwhelmingly a Brittany speciality, with the great majority of logged sightings coming from that region of France. Smaller but reliable numbers turn up around Jersey and Guernsey, the Bay of Biscay, Northern Ireland, Wales, and further sites in England and Zeeland in the Netherlands.
Mapping where Hooded Shrimp is logged…
Brittany in France is by far the strongest region for sightings, with further records from Jersey and Guernsey, the Bay of Biscay, Northern Ireland, and Wales.
There's no strong seasonal signal in the sightings, and the water temperatures they're found in (roughly 9.8 to 15.8C) cover much of the year in these regions, so they're a reasonable year-round find.
Look for a small, mottled, semi-translucent shrimp tucked into rocky crevices or weed, with a distinctive arched hood over the head. It stays close to cover rather than swimming openly, so a slow search with a torch works best.
Exact size data isn't confirmed for this species, but like most crevice-dwelling shrimp in this family it's small enough to be easily overlooked without a close, deliberate search.
No. They pose no risk to divers and simply retreat into cover if disturbed.
Site and sighting data is aggregated from diver logs, iNaturalist and GBIF. For taxonomy and conservation status:
Sally Lightfoot Crab
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