Alex Mustard / Portrait of a Nudibranch (Flabellina pellucida) on a kelp frond with star trails. Gulen, Norway. North East Atlantic Ocean.

Alex Mustard / Nudibranch (Flabellina lineata) in aquarium, taken in the field in Gulen, Norway. North East Atlantic Ocean. Collected for scientific research.

Franco Banfi / Nudibranch (Flabellina affinis) Vela Luka, Korcula Island, Croatia, Adriatic Sea, Mediterranean.

Alex Mustard,Alex Mustard / Nudibranch (Flabellina nobilis) photographed in the field aquarium in Gulen, Norway. North East Atlantic Ocean.

Alex Mustard,Alex Mustard / A nudibranch (Flabellina nobilis) feeding on a solitary hydroid (Tubularia indivisa), note how the hydroid is bent back as it is pulled into the nudibranch's mouth. Gulen, Bergen, Norway. North East A...

Wild Wonders of Europe / Banfi / Nudibranch (Flabellina affinis) on algae (Caulerpa taxifolia) Larvotto Marine Reserve, Monaco, Mediterranean Sea, July 2009

Wild Wonders of Europe / Lundgren / Nudibranch (Flabellina lineata) on seaweed, Saltstraumen, Bod, Norway, October 2008

Wild Wonders of Europe / Lundgren / Nudibranch (Flabellina verrucosa) on seaweed, Saltstraumen, Bod, Norway, October 2008

Wild Wonders of Europe / Lundgren / Nudibranch (Flabellina verrucosa) on seaweed, Saltstraumen, Bod, Norway, October 2008

Solvin Zankl / Nudibranch {Flabellina rubrolineata} Lembeh Strait, Indonesia

Sergio Hanquet / Nudibranch (Flabellina affinis). Canary Islands, Tenerife.

Pascal Kobeh / Mediterranean / Pink flabellina nudibranch(Flabellina affinis), Canary Islands