As its name suggests, the violet sea slug is a striking purple colour and is best seen underwater – especially in the summer when they are most common.
These sea slugs, or nudibranches, are molluscs just like land slugs and snails, although they are very different. Many nudibranches eat stinging animals called hydroids, which are like small anemones on stalks; they can pass the stings through their digestive system and collect them on their back as a deterent to predators.
The violet sea slug is a beautiful purple colour with white tips to the pointed growths (cerata) on its back and head. It has two antennae, called rhinophores, and has two more either side of its mouth which it uses to feel for food.
The best place to find violet sea slugs is underwater. If they were seen in a rock pool they might appear like a very small beadlet anemone underwater - like an anemone they would not hold their shape if they were lifted out. They occur in large numbers on shipwrecks and if you were to snorkel down to the shallow wrecks off Cley or Weybourne you might see them as tiny purple dots - these are very small animals which need careful searching to find.
Numbers increase after their food appears in the spring, they are most common during the summer.
Submit your violet sea slug sightings to Norfolk Biodiversity Information Service (NBIS).