A beautiful flabellina nudibranch displaying her cerata in the ocean current. Flabellina is a species-rich genus of sea slugs (nudibranchs). Unlike other nudibranchs, they are characterized by cerata: their backs are covered with cerata arranged in groups on pedestals. These cerata are skin extensions that enlarge the skin surface of the animals. The main function of these cerata is to support respiration. Their beautiful appearance with the colorful cerata also serves their defense.