As to checking for undesirables, are there any streams/rivers in the vicinity, or other ponds that might in a flood drain to yours? CC will consume fingerlings, and if they're hungry as they likely are, they could consume several of them. More problematic would be if some GSF have gotten into the pond from neighboring bodies of water; GSF would eat fingerlings with great gusto. If they're in there, you would most likely get some in the traps. Even better would be just to fish for bluegill with light line and a small hook and live bait; if there are GSF in the pond, you'll catch some. If they are present, you would be wise to rotenone before stocking.