Spanish dancer, the blood-colored nudibranch
One of the biggest nudibranch on Earth,
the Spanish dancer is a nudibranch of the Philippines you definitely want to meet.
Fancy moves, elegant colors, a size made for all eyes and the opportunity of watching a beautiful dance display underwater are just a few characteristics amongst others that make us want to spot this fantastic nudibranch.
Carabao island counts with a lot of different nudibranchs and one that we really like is Hexabranchus sanguineus. Spanish dancer in the Philippines can be seen in a few dive locations and when you meet it, you don’t forget the encounter.
Learn more about this sea slug and you will be curious to observe it under the waves!
Classification
Spanish dancer is a marine gastropod mollusk in the family Hexabranchidae.
Its scientific name Hexabranchus Sanguineus can be translated as “blood-colored six-gills”, and is a perfect description of this bright orange-red nudibranch with six (6) gills displayed on the back of it’s soft and flattened body.
This dorid nudibranch is probably the biggest nudibranch on Earth. In the Philippines, we have seen Spanish dancer reaching a size of at least 40 cm (16 inches).
Spanish dancer: a dorid nudibranch with six gills
While most dorid nudibranchs count with one set of gills, that they use to breath, Hexabranchus sanguineus, however, counts with 6 separately attached gills making it easy to identify (apart from its color and unique size obviously).
The gills are the flower-looking stuff at the back of a nudibranch.
Did you know that nudibranch actually means “naked gills”?

You can observe the multiple gills on the back

Why do we call it “Spanish dancer”?
The common name of this nudibranch comes from the visual effect it produces while swimming.
Spanish dancer, like other nudibranchs, crowl on the bottom of the reef, but when it feels threatened it can swim away by flapping its gills and appendages.
The movement of the body simulates the movement of the Spanish flamenco dancer’s skirts and that’s why we call it “Spanish dancer”.
What does a Spanish dancer eat?
This big sea slug has a strick diet based on sea sponges and tunicates.
The sea sponges are more than just a source of food. The Spanish dancer can absorb the toxins that protect the sea sponges and use them to defend itself.
The bright orange and red color it displays is a way to tell any predator around that the Spanish dancers’s meat is not on the menu.
A rose as a gift to the ocean: reproduction
Hexabranchus Sanguineus are hermaphrodites. However, they can not reproduce alone, they need a partner to fertilize the eggs.
The eggs can be distinguished from other species of nudibranchs thanks to their bright pinky coloration and rose shape.
The parents will provide the eggs with the same chemicals they extract from the sponges to protect them since they won’t care for the eggs after depositing them on the reef.
It is believed that the shape and color of the eggs are part of the romantic ritual during mating.
Best time to look for a “Spanish dancer” in the Philippines
We are lucky to count with the presence of the beautiful Spanish dancer nudibranch in the Philippines and around the reefs of Carabao Island.
Spanish dancer is not common to spot during the day. However, our experience tells us that in some spots around the island it can be seen anytime of the day in very shallow water. This happens during the months of May and June.
Your chances to experience the special swimming dance of this nudibranch are higher during a night dive.
It is also a good excuse to go underwater during the night and encounter lot of different critters that will amaze you!
A night dive on Carabao Island will never disappoint.
Check out our short presentation video of a Spanish dancer nudibranch in the Philippines, filmed around Carabao island
And you, have you met the Spanish dancer nudibranch?
How was it?