Phyllidia coelestis

Scientific name : Phyllidia coelestis

No external gills, hard back with tubercles arranged along longitudinal ridges. Colour: black amongst the ridges, blue along the ridges, yellow on the large tubercles and rhynophores. The longitudinal ridges meet toward the tail with a Y shape. Blue, expanded mantle edge. 6 cm.
Very similar to Phyllidia varicosa. Differences: it is smaller (in the maximum size), P. varicosa has no Y shaped ridges, it has a longitudinal black line along the underside of the foot. The expanded mantle edge with fine blue tubercles is typical of P. coelestis.

Associated organisms
Whit sponges, its food.