my neighbour has so many fish in his pond that it looks more like fish soup, with some big ones but mostly little ones, he says that there used to be twenty decent ones but they have bred so much and he don't know what to do with all the small ones if he takes them out, any sugestions welcome.
Selling to a shop may be the best option. Once people know where there are a lot of goldfish, you may find your fish stock dwindling (probably your big ones) and damage or missing other stuff too.
Sorry to be negative, but I speak from experience.