It seems like a case of territorial aggression. It is common for clownfish to turn against each other when settled except when they are a pair. You might get away with aggression if your tank is big enough.
Cheers
They sure look very similar to those we used to have at our shop except for the color of their shell.
http://www.m3morph.com/main/products-page/in-stocks/invert/nassarius-snail/
Cheers
That is my tot when I first saw them appear in supplier's list. I was thinking "Aren't these fish those shown in Natgeo TV that crush corals!"
Guess I was mistaken. hahahaha
You keen in Chromis limbaughi? Our supplier has them in stock last week together with the Flathead perch. If you keen, we can check if they still have them.