well he was originally intended for my 250 gallon which houses, 1 motoro stingray, 1 leopoldi stingray, 1 moonlight gorami, 2 blue acara, 2 fire eels, 2 blue gouramis, 2 brichardi, 2 red irian rainbows, 3 bala sharks and 6 congo tetras. BUT he was territorial and kind of aggressive towards the acaras. Then I took him out of there and put him in a 15 gallon tank that is supposed to be my feeder tank. It is not lighted so I did not like him in there. I then moved him to my sons 30 gallon tank which houses, 1 red-tailed black shark, 1 irridescent shark, 1 bala shark, 1 berney's shark, 1 pictus cat, 1 chinese algae eater, 1 pleco, 2 weather loaches. There were 3 angelfish in ther too, but now two are dead, probably thanks to Spike but he seems to not bother anyone else and seems happy in there. My sons tank is not big enough for all these fish though so I wanted to put him back in the big tank, but now I am scared to do that. I don't want him to terrorize those fish