Interesting question. I would fish it to see what fish is nipping. Considering stocking rates your LMB could have overpopulated and stunted but 2 years doesn't seem like long enough for that. IMO don't waste your money on minnows which at best will be a temporary fix. Until you find out what the fish are I can't help anymore than that.

0.7 acre pond stocked 2020, LMB, PS, YP.