Yes they are. I bred them for a while I had 5 breeding pairs.3x Standard occy, maroon, clarki, I got out of salt about the time the designer clowns got huge. All were very aggressive especially with eggs or young but the maroon were the worst. I simply bred them because it was pretty easy and everyone wanted Nemo! The other two I just happened upon. During that 3 or 4 years I learned to hate clownfish. I already hated human clowns......
Sorry for the late reply, but as you now know its a Ceylon puffer... they basically live in full S/W at maturity... my friend used to keep one as well, great fish...