You can consider feeding them store bought fish food. This is by far the least worrisome. Get your population down accordingly and feed them till they are fat, catch/eat them, then restock. Watch out for overfeeding that can lead to high nutrient levels however.

Otherwise, getting some BG and LMB would be a bit more typical. You, now, need to be concerned with their population control. Catfish will eat most anything.

There maybe minnow types for your area that could help, but I am not going to guess at what might work. Usually, if you add minnows to an established pond, they are just expensive snacks.

Anything you put in will have to have the habitat considered. Certain types of minnows need grass-like vegetation to reproduce or underwater shelves to lay eggs on, for example. Bluegill like to have some shallows with fairly consistent water levels for nesting, as do bass.

The above is just my 2 cents from hanging out here at PB. I am sure others will have some real experienced advice.

Fish on!,
Noel