I read that it takes a while to see how aggressive they will be 10 or 12 or something like that. I had one that was small and didnt bother any tankmates. Infact it got bullied by a 2 inch datOf course, I have no problem having him in his own tank, I’d rather it be that way rather than lose other fish haha. But I’m kinda suprised that him and the fahaka are getting along so good. I just fed him for the first time, and actually he did not eat at the store last night when I picked him up, but he AGGRESSIVELY took down 6 pieces of krill and some bloodworms tonight and still wanted more.