Flabellina babai

Solitary shot of these two nudibranchs near the end of the dive.

Hypselodoris picta

Nudibranchs breathe through the branchial plumes in a rosette, the circular arrangement, on their backs.

This particular nudibranch was one of the biggest that I have seen.

It measured between 13-15cm. 

Here you can see the dark blue rhinophores on its head.

The rhinophores are chemosensory organs which function as scent or taste receptors.

Anglerfish - Monkfish, Lophius piscatorius

We saw this Anglerfish whilst diving in Gibraltar.  It was sitting quietly on the sand and has nice appendages around its mouth.

The Angler, Lophius piscatorius, is a monkfish.

It is on the Greenpeace seafood red list, commonly sold fish which are at high risk of being sourced from unsustainable fisheries.  It can be seen in many Spanish fish markets.

Simon from Simply Diving, Costa del Sol, Spain

Fringed appendages line the body and head giving it the appearance of seaweed assisting greatly in camouflaging and making it quite hard to spot.  

The male Anglerfish has no other purpose in life other than searching the abyss for a female and on encountering one latches on to her with his sharp teeth.  He then gradually fuses with her, permanently connecting to her skin and bloodstream.  The male loses its eyes and ALL of its internal organs except for the testes.

More Anglerfish facts (and fiction):

The Oatmeal explains the Anglerfish male and female relationship in the graphic strip: How the male Angler Fish gets completely screwed.

Feeding Hypselodoris cantabrica

Nudibranchs are carnivores grazing on algae, anemones, barnacles, corals, sponges and also on other nudibranchs.  The two highly sensitive tentacles, called rhinophores, on the top of their head locate their prey.  The alluring colours of nudibranchs come from the colouring of the food they eat.  Some nudis retain foul-tasting poisons of their prey and then secrete them as a defense against predators.  

Caricoles - Slug Snacks

Disgusting!