The Spanish Dancer Hexabranchus sanguineus is a dorid nudibranch, a marine gastropod mollusk. They obtain their common name from their resemblance when swimming to the skirts of a Spanish Flamenco Dancer. Their scientific name means six blood coloured gills.
The name Nudibranch , pronounced ” nudibrank” literally means naked gills and the respiratory organs or gills can be seen on the rear of the Spanish Dancer. Some species of nudibranch have pouches into which they can withdraw their gills but the Spanish Dancer cannot withdraw its gills.
Spanish Dancer’s have an elongated oval shape. The colour varies greatly from a bright red to an orange with red spots. Inbetween are red mottled with white and on occasion red mottled with an orange or yellow colour. The rhinopores and the gills usually match the main background colour. They grow up to 60 centimetres in length but they are usually smaller. The ones in the images are around 35 centimetres. When crawling along the bottom the mantle is folded back towards the body. When they are uncomfortable they fold the mantle out and have the ability to swim by undulating the body. This is quite a sight to see and can be seen in the video below.
IN THE WILD
The Spanish Dancer is a nocturnal feeder and is usually only seen out at night but on rare occasions they can be seen during the day, usually in a dark crevice. They have the ability to secrete toxic substances which provides protection against predators. When lit up at night they usually head for the shadows and have some light sensing ability. The prominent rhinopores on the front of the Spanish Dancer are used to detect chemical scents in the water. These allow them to track down food sources and possibly may assist in finding others to mate with.
The Spanish Dancer is found across the tropical and sub tropical Indian ocean and in the west Pacific,from Africa to Hawai and Australia to Japan.
The Spanish Dancer feed on sponges and absorb toxins from the sponges which provide protection against predators.
They are simultaneous hermaphrodites and mating takes place by darting. The individual who darts the other first becomes the dominant male and the other the female. Eggs are laid on a solid substrate in the form of a long ribbon and when they hatch the larvae become planktonic before growing into adults.
The Emperor shrimp, Periclimenes imperator is commonly found living on the Spanish dancer. Often they will hide under the mantle when they see a diver approaching. Sometimes there is more than one on a specimen. If you look carefully at the image below there is one on the nose and one near the gills.
SPANISH DANCER CLASSIFICATION
Species: Hexabranchus sanguineus