Hypselodoris Cocktail in Lembeh

On a dive last week i found this cool Hypselodoris at Hairball 2 – one of the famous Black sand Muck Dives of Lembeh Strait. According to Nudi books it is a “Red-Blotched Hypselodoris”. No matter how it is called – it is a very beautiful Nudibranch and i really kept watching it until my computer started protesting (it was at 33 meters). But what impressed me the most, was the fact that it was sitting there together with a Giant Hypselodoris (hypselodoris apolegma … you can see it in the background of the picture) and there was also some egg mass. Now i am wondering how there can be two different species sitting together with Eggs on the same little piece of sponge. Where they mating? Or was it just coincidence? Just another good dive in Lembeh!