Both BG and LMB also tolerate salt/brackish water well to a point. Both are found in the marshes and for example Lake Pontchartrain. We need to get PaPond or a chemist on here to address how much and how to deal with salt residue in the dirt once the pond is empty. Assuming you want fresh water fish in the pond then I would pump out the pond if you can but not on to your grass or trees as it may kill them and ruin the soil.