Welcome to this Forum, it's a great place and most all of your questions can and will be answered. But I am not the expert when it comes to correcting the type of problem you seem to have. Others will most likely jump in. I will suggest you raise some money and have the lake shock surveyed so you might get a path to get to your goals. Throwing crappie into the mix right now is most likely not the right path to take at this time based on your comments about all the small fish and the regular stocking that has taken place. Another thing is you have two predators all ready in the lake and both are most likely on the top of any list of pond predators. Contact Bob Lusk here, he will guide you to your goals.
