Yep exactly. Good news is he gets big and will pass the others! Bad news is he usually out grows the other in the tank and then you gotta worry (usually) about him beating on the others. Make lots of territories/hiding for them all!
The midas will probably terrorize and maybe kill the cons and sevs while he is small, but he will soon be bigger than them and then it's pretty doubtful he will let them live in 'his' tank.