My pond is about 1 1/2 acres in size in Northeast Nebraska. Spring and rain runoff fed. Estimated by locals to be around 70 to 80 years old. Well stocked with LMB, BG and Crappie. In the last week I have noticed a tremendous amount of small snails in the water along the bank. Are they something I should worry about? Should I stock some RES to control them? Would they survive this far north and are there any negatives to RES with my current population? Thanks in advance!