1/2 acre pond - spent summers raking weeds out constantly or buying Aquathol Super K. Stocked 5 GC and the Osprey got 3 of them - so stocked 5 more and the Osprey got two of those - so have five total now, Within two years they completely denuded the pond of any weeds - so guessing 5 is too many for this size pond. They are all now 25" long (in 5 years) and if in the area when I am feeding the LMB and BG, they will help themselves to all they can get.
Would recommend starting slow and adding if you need to. Think about stocking during a time of the year when the Osprey are not so active if you have them in your area. We do not have many Eagles here, but they might be an issue also if you have them. The young 12" GC like to bask in the upper part of the water column during hot days and make for easy pickings.
