as far as im aware u shouldnt. as for space, i think ud have room for more as thats fairly big (im guessin its inches). i was considering gettin a 90x45x45cm tank and was told id get around 4/5 whites in there so i think ud b ok. red eyes are smaller so i dont see why not. it depends tho. with the 3 u have and theyll have more room if u leave it at that. just because u can fit more in doesnt mean u have to. thats my opinion tho. see what some other people say