UPDATE!

So I have moved in and little worse than I originally thought. It is over populated to the max with Black Crappie. All i have caught minus the Cats are these little runts. The biggest one Ive caught is 3inches. Its a .60 acre pond with aerator running.

What are my options minus killing everything off.

I was thinking I go out and catch or buy some 12-14in bass and let them go buck wild?

The channel cats I think I can get rid of. Ive been feeding them and hooking them while they are eating. Not the most sporting way but it is quick. Ive caught 4 18-20in long ones, and Ive only seen about 5 more while feeding. I understand there are probably more but as long as they are not reproducing I can knock them out.