O.K. That gives us some direction.
First off, it's a lot easier to type out acronyms, so here's the list to the ones that we use the most here:
http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=92442#Post92442 With a Largemouth Bass/Bluegill/Catfish pond, you will have to be removing fish every year or they will overpopulate and become stunted. Remove roughly 20# of LMB every year and remove every CC that you catch, and replace that number of CC every year. That means that the Bass/Catfish will eat most of the Bluegills, and once they are gone, they won't have enough food to continue to grow. They'll start getting skinnier and skinnier. If you want to swim in the pond, BG are known to peck at swimmers, and some people don't like that.
This is only one option, but you probably should take a look at a Hybrid pond. Hybrid Bluegills, Hybrid Striped Bass, some Redear Sunfish to keep any snails in check if you or the kids someday wanted to swim in the pond, Fathead Minnows and Golden Shiners for forage fish.
Typically you want approx. 20% of the surface acreage of the pond to have cover for the fish to hide in, young of the year to use for cover, and to give the fish something to congregate around. Keep it away from any swimming area for safety reasons. There's a company in Northern Illinois that makes cover for fish out of recycled vinyl siding, which is one good option for cover in the pond. If you don't have that much cover in the pond, there is a good chance that the predators will have too easy of a time eating the forage fish and the pond will become unbalanced.
If you want to make your own, read this thread:
http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=92463#Post92463 I'd make sure there are no other fish in the pond before you start the stocking process. That's because if there are larger fish in the pond, a lot of the stocked fish might become expensive fish food.
When the catfish died, was the pond or surrounding land treated for any weeds, algae or bugs prior to them dying? How long has the pond been there, and were there any fish in it before?
You can send water here to have tested. Be aware that something that was put in the pond a year ago, either intentionally or unintentionally might not show up on the test this year.
http://soiltesting.tamu.edu/ There are other labs around, maybe someplace closer that someone else on here might know about.
If you know that there aren't other fish in the pond, here's what I'd do if it was mine.
No fish and good water:
Stock 5#-10# each of Fathead Minnows and Golden Shiners this year and stock 200 Redear Sunfish fingerlings this year. The RES should be available this Fall, the FHM and GSH should be available too.
Next spring/early summer before the water gets too warm, stock 500 Hybrid Bluegills 1"-4" and 25-40 Hybrid Striped Bass 4"-6".
That's it. I say get the RES in this year, because sometimes they are in short supply, especially in the spring, so get 'em while the getting is good. The FHM and GSH have to reproduce and get the forage fish food base established before adding predators, which are the HBG and HSB.
Aeration: Run the diffusers in the deepest part of the pond for the late spring, summer and early fall, in late fall move one diffuser to water that is about 3' deep and about 20' from shore. Shut off the one in deep water and just let that one run all winter long, 24/7. Keep an eye on the pressure gauge so that the compressor is still running in it's operating range.
If there are other fish in the pond, or you don't know for sure, AND you don't need the pond for drinking water, then I'd drain the pond down as far as I could, use hydrated lime to make sure that there aren't any fish survivors and let the pond refill with water. In early fall, when there's at least 4' - 5' of water in the pond, I'd test the water with a pool pH test kit. If the pH is down below 8.5, get the FHM, GSH and RES in there before the winter.
If you can't drain the pond and you don't know if there are fish in there or not, then we have to do some creative thinking.........