Beautiful Nudibranchs mating

On yesterdays afternoon dive at “Nudi Falls” i spend the whole dive photographing Gobies – so i had a 100mm lens on the camera. And i really started regretting that, when reaching Safety Stop level at the end of the dive: Just below the boat was this beautiful pair of Nudibranchs mating. They were Hypselodoris iacula (Fishnet Hypselodoris or Magical Hypselodoris). The adults of this species are 5cm big – so two of them are a relatively big size to shoot with a 100m Macro. But as this type of nudibranchs is one of my favourites i still took some (ok … a lot) shots. Like many Nudibranchs their colours really pop under water – even without light or strobe.
In this picture you can see the mating process very well: The sexual Organs (genital papilla) on the upper left side in the picture are connected. Some species of Nudibranchs copulate very quickly some others take a loooong time – specially Dorid Nudibranchs (to which group also these Hypselodoris belong to). After mating the Nudibranchs will stick eggmass ribbons to rocks or algae. let’s hope their eggs will do well – because of course we would all like to see more of this colourful Nudibranch species.