I would like to be able to swim in it and I may add fish later. I pumped it dry last summer and where it is holding water it was the blueish type of clay that if you step in it you sick up to your knees. I think I will dig it out a bit and set clay aside and line it like suggested. the side have a lot of stone in it and I think thats were I am leaking. I also need to tapper the shore line a bit.