I have a newly cleaned pond and kids are requesting no fish. I think the bluegill had gotten out of control and they were often bitten pretty hard, I also was torpedoed in the back once (possibly a careless bass lol). To my knowledge we had bluegill, bass, perch, and grass carp. So, what fish are necessary to keep the pond healthy, but the least of a nuisance to swimmers? We are in NW Ohio and do have pet ducks, if it matters. I am also planning on buying a new fountain/aerator to keep it as healthy as well.

Ducks will make a pond nasty to swim in.

Put in a few dozen Gambusia (mosquitofish) to eliminate mosquito larvae. They only get about two inches long, and won't bother people swimming. They are native livebearers, and will, in the first summer, multiply manyfold.

Felt,

If you were going to go in with only one fish you might consider smallmouth bass. The small ones will eat the things your bluegill were eating and the larger ones will eat the smaller ones. There will never be as many fish as you had when the BOW contained bluegill. You wouldn't need aeration though it wouldn't hurt to do it. Buck and Thoits noted that their SMB monoculture could be cropped heavily with no detriment to the Spring Standing weights noting in at least one BOW that the annual crop was larger than the BOW could likely carry. A BOW will carry a greater weight of SMB than LMB and a lesser weight than BG. They are kind of a blend of LMB and BG in terms of the foods they tend to eat.

Provided they could reproduce in your BOW they may be a good choice. If Gambusia are native in your region, I do like John's rec or perhaps other local small minnows. Small minnows could be a prey fish for the SMB as well.

I second the idea of just SMB for the same reasons. They will never bother swimmers and from my experience with this; they will grow to around 9"-10" long. If you have difficulty finding SMB my next option is HSB(hybrid striped bass), third and lesser quality option is LMB. Start with around 40-60 per acre (15-20/0.3 ac) by themselves. They will achieve their natural density per acre after 4-5 yrs. Note the HSB will not reproduce and will need periodic restocking as you notice fewer are present. The HSB will respond well to pellet feeding to entertain the kids.

A few pellet fed CC will entertain also, with their heads sticking up and circling whilst scooping up pellets. They won't bother swimmers either.

Consider RES as well for snail control, perhaps combined with gambusia and SMB. I know this is 3 species not 1.