I have somone who want to give me a small livingstonni (about 3 inches) the only tank I have that it could go in is my 55 with my green terror. Right now he is living with a 2" rainbow shark that kinda got tossed in there. He isn't aggresive toward the rainbow shark (but maybe they are buds). I plan to get another tank soon but would the livingstonni be ok to grow in this tank if there isn't any aggression? Thanks.