I've had a leak in my pond for ages, it randomly loses water and I could never work out where the leak was... so yesterday I bit the bullet and emptied and pulled it apart and found the leak. It was a small cut in the liner, not sure how it got there but I think I'll just try patch it up with multiple layers of duct tape / pond liner layer / duct tape. It's $100 for a new pond liner. It's pretty annoying having a leaking pond.
It seems I only have two Bass left. (originally had four). No Crayfish left either, it's possible they escaped or were eaten. This Bass is around 6 1/2 inches. One year ago they were around 5 inches.