I don't agree, they get a far worse rep than they deserve, I had a blue devil, yellow tail and a velvet, never had any problems other than their colors ended up fading. They aren't chickens, but when kept with larger fish that aren't really passive, it shouldn't be a problem. They were the smallest fish in my 180 and never bothered anyone, eventually they were in a 45 with whatever I was qting. They spend time with 3 angels without a problem.