When I mentioned the kids "feeding" the fish that was an overstatement, what I meant was ever week or so they may throw a few pieces of bread in, we dont regularly feed.
I've been looking around and found this product: https://www.lakelawnandpond.com/captain.aspx?ItemGroupID=26
Which sounds interesting, also the barley I was thinking may help.
As far as a UV I beleive my pond is 300-400,000 gallon I dont know how realistic UV would be for my size.
Also if you look at my test water jar the green is throughout the water not just top floating.