not quite so. There are some types that are commonly labeled as "caution", but they almost never nip. "at own risk" should apply to all fish IMO. I've seen yellow tangs, nasos that nip corals so it all depends on the fish.
Good choices are the schooling bannerfish and pyramid butterflies. (banner must be of the species h.diphreutes. I have 3 of them as of now and I'll post a pic of them for you if you'd like) THere are other butterflies that prefers certain corals. So some is good if you only have SPS and some are good when you only have softies or LPS.
She should be reef safe and generally is.
She should eat aiptasia but she doesn't.
She doesn't touch the corals but she does eat the antenaI off my snails so that they curl up and die and doesn't bother with my aiptasia at all. Maybe when she grows bigger she might have got a bit more cheecky and started having a nibble at the corals, but we'll not find out since she has been turfed out of the reef tank and put in with the dogface and trigger.
I really does depend on the fish and on the corals and inverts in question.
I am very new......but I stay CLEAR away from anything that says with caution. I absolutely love all the angelfish and dwarf angels.....and it always figures when I see a fish...usually the prettiest ones(lol) are not reef safe. I have a small fortune invested in my corals...to me its just not worth chancing it......and if it happens to go after a coral...just try getting it out...mission impossible!!!!!!!