It is always incredible on a night dive to see a Spanish Dancer; we don’t mean a lady in frills with a set of castanets, we mean the stunning nocturnal red sea slug. As one of the largest reported nudibranchs some have reached lengths of up to 40cm’s. Its latin and common names both are some of the most descriptive names we have come across. Hexabranchus sanguineus means six gilled and blood coloured, while Spanish dancer refers to its graceful whirling swimming movement and the frilled skirt like edges to its body. It belongs to the nudibranch family which also is a descriptive name as it means bear lungs, literally describing the fact that their gills are exposed as they are on the outside of its body.
It feeds on sponge and tends to eat a lot of the Halichondria sponge which contains toxic chemicals to evade being eaten by most of the other members of the reef! The Spanish Dancer is able to isolate and modify this toxin and store it in its eggs and skin.
This ensures that their eggs and themselves are a rather distasteful meal for any potential predators.
Their breeding is done throughout most of the year and they only stop during the coldest months of the year…when obviously the cold does not create the mood for romance. The eggs are stored in characteristic bright red ribbons which can often be found on rock outcroppings around the reefs of Sharm. Many of you have probably seen them, without ever realising exactly what they are.
They look like a red tissue rose wafting in the current and are beautiful to look at…although you now know they taste nasty!
They move along the reef in a crawling motion but when threatened they unfurl their edges (the parapodia) and whirl through the water like a Spanish lady dancing.