clownfish are not really aggresive. they are territorial and it's not easy to put different species together. i would recommend purchasing a pair. they shouldn't really bother any other kind of fish and they are definitely reef safe.
An old roomate had a Maroon for over 8 years. It was a little nippy now and then, but not too bad. My percula was a lot mellower.
(What's with all the exclamation points today? No more coffee people!)
depends on the fish. my clown is a killer. pretty only docile when she's the only fish/creature in the tank (leaves inverts alone-sometimes), she's more semi aggressive, killed two or so damsels, oh i forget the rest...
but for the most part they are peaceful...
My percula isn't aggressive with the other fish but whenever it comes to feeding time or cleaning the tank he goes crazy and bites the hell out of me. <img src="graemlins//yell.gif" border="0" alt="[yell]" /> I have to fight him off any time I try to rearrange anything in there. It doesn't hurt much but it jolts the hell out of me!
IMO
generally the least aggressive is the false percuala then the percula
and more aggressive is the maroon and/or the tomato
but, hey, these are fish(living cratures) so there is always gonna be exceptions
Striker,
I had a Percula that did the same to me...he bit the hand that feed him (mine!!). I have a Maroon now who is a very timid, pleasant little guy.