i don't think that they turn into killers. i have two gold rams, a pair. the two had eggs few times now. they chase all kinds of fish around when have eggs, even my adult discus, but never killed anything. i have tetras: like white skirt, cardinals, barbs. when there are no eggs, they rarely chase any fish. but do note that they were in my 55 before and now in 125 gallons tank. possible that the size of the tank matters.