If you have 2" pbass in your 120g and put the 2" clown loaches in a smaller tank to "grow them out" to put them in the 120g at 5", then the pbass will be WAY too big to for 5" clowns. You have to get 8" clowns with 2" pbass, then maybe you've actually got some time. Clowns will never catch up to pbass like that.