Likely to be tritoniopsis, eats the coral you found it on, kind of slowly, cool to watch. If there are several they may reproduce. http://www.seaslugforum.net/find/triteleg
It's hard to tell from a short video... If he had a still picture might be easier to id. But to me looks a lot rounder and flatter than the other one you showed us .
Perhaps discodorid or platydorid?!
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.