Sorry, this question seems kinda noobish but Ive seen so many different rules and fish per gallon, and I figured the best reference would be the people who have experience with them so.... I want to know if 3 rbp's would go well in a 55 and if 3 would be enough (in your experiences, i know that it is kind of subject to fish personalities) to keep the aggression down. .. If that doesnt sound right to you, im open to suggestions as well.