hmmm... one year I had bought a few fish and was fairly excited to find a black koi of some type, still fairly small, I placed them into the pond and watched for a few days. The black fish was difficult to see against the black liner unless I was feeding and it came to the surface. One day I noticed I didn't see it anymore, looking frantically and feeding fish to see if it would show, I happen to look across the pond and saw my bullfrog. Yes I thought the unthinkable, so I grabbed my net and scooped him up and pried its mouth open. To know avail did I find signs or remnants of my fish. A few days later I was cleaning my prefilter basket on my pump and found the bugger, dead unfortunately. It must have gotten too close to my skimmer inlet, brushes and net and got sucked in..