i have four clown fish... 3 of them play but ever since i got my second clown he looks at the wall all day and plays every once and a while... he doesnt hide just sits and looks at the tank wall...wats it from?
your tank could be too small, there could be bullying, it could just be warmer on that end of the tank. i'd consider a bigger tank and if that doesn't solve the problem then i would split them into 2 tanks.