If you plan to stock grass shrimp, make sure there is at least some sort of cover in the pond for them or they will likely be eaten. Myself and a few others on here have recently stocked our ponds with grass shrimp, but it's too soon to tell how they have faired. One member(bobad), has added wild caught ones to his pond and has had great results.
I think a small like a half dozen of so CC should be OK in your pond and won't eat you out of house and home. They should also help keep your HBG from over populating. The HBG will hammer the snot out of your FHM, but you may be able to maintain a self sustaining population if you include a few pallets and give some them somewhere to hide as well as keep the HBG pellet fed. I have seen ponds with only CC maintain FHM, but not sure with the addition of HBG.
