Hippolyte varians
Colour-changing prawn most reliably found among Zeeland's seaweed in 9-15C water, seen uncommonly across Dutch, UK and Breton dive sites.
A small, translucent prawn only a few centimetres long, its body colour shifting to match the seaweed or algae it sits on, from green through red to brown. Look for the fine speckling and the way it seems to almost disappear against its perch rather than swim in open water. It usually clings motionless to weed fronds or eelgrass rather than crossing open sand, which is often the giveaway when you spot one at all.
Divers usually find it sitting still on seaweed or eelgrass, relying on its colour match rather than fleeing when approached. It tends to stay tucked into weed beds and rocky, algae-covered ground rather than open water, so slow, close looking pays off more than wide scanning. Most logged sightings describe it as uncommon rather than easy, so it rewards divers who check weed fronds carefully rather than swim past them.
Its body colour tracks the seaweed it lives on, shifting between shades of green, red and brown as it moves between different algae, which is an unusually direct form of camouflage for a shrimp this size.
Sightings are logged year-round with no strong seasonal pattern in the data, consistent with a cool-water species comfortable in the 9 to 15C range typical of these northern European sites.
Zeeland in the Netherlands is by far the strongest area for this species, with sites there far outnumbering anywhere else logged. Outside the Netherlands it turns up in Brittany in France, and around Northern Ireland, Jersey and Guernsey, and Wales in the UK, with a handful of records from Nordland in Norway.
Mapping where Chameleon Prawn is logged…
Zeeland in the Netherlands is the standout region, with far more sites logging it than anywhere else. It is also found in Brittany, France, and around Northern Ireland, Jersey, Guernsey and Wales in the UK, plus occasional sightings in Nordland, Norway.
There is no strong season in the sighting data, so it is best treated as a year-round find in the cool water it favours, roughly 9 to 15C.
Look for a small translucent prawn a few centimetres long sitting still on seaweed or eelgrass, its body colour matching whatever algae it is perched on. It is far easier to spot by checking weed fronds closely than by scanning open water.
It stays small, typically only a few centimetres long, which combined with its camouflage makes it one of the easier animals to swim straight past on a dive.
It can shift its body colour to match the seaweed it is living on at the time, moving through shades of green, red and brown as it changes perches, giving it its common name.
No, it poses no risk to divers. It is a tiny, harmless crustacean best appreciated by looking closely rather than touching.
Site and sighting data is aggregated from diver logs, iNaturalist and GBIF. For taxonomy and conservation status:
Sally Lightfoot Crab
2,422 sites
