My rocks are in the water, I have a small shelf, 6-8 inches down, and the rock sit in the water so no liner shows. I had it that way last year, and when I rebuilt the pond this year, I did the same thing. I have had fish get in between the rocks and get stuck on 3 occasions so far this year, and I had my first fatality from it this weekend. First time, i had a silver koi missing for over a week, I searched for him, looked in big gaps in the rocks, couldn’t find him. Well I topped off the pond when the weekend rolled around, and suddenly the next morning he is back. tore up on his sides, and missing part of his tail fin, but alive and well, it’s been a few weeks now and he healed up fine. Second time, again, I was topping off the pond, and in between 2 rocks, water is splashing out... lift up a few rocks and one of my goldfish (black) is stuck in there, swims out, floats down to the bottom and lays there, I was sure he was dead. Go back a few hours later he is swimming around, he is now my black fish with a white side because his side was pretty torn up from being stuck there. Not sure how long he was missing, the goldfish I don’t keep track if very well, but I notice when a koi goes missing. Now this weekend I notice my yellow butterfly is missing... not sure for how long, must have been sometime during the week when I was working and usually toss in food and head off. Well of course I grab the hose... he's stuck in the rocks somewhere, better get him some more water to swim out. No go, not this time, he’s gone, and the bad thing is I still can't find his body, just way too many nooks and crannies he could be in. Anyway... I never had this issue last year and the koi were much smaller then, maybe that is the difference they were small enough to get out easily then, but now they are at that point where they are still small enough to get in, but can’t get back out. There are probably 4-5 of them that could still get in between rocks if they wanted, I’m sure by the end of the summer they will be big enough it won’t be an issue, but I don’t want to lose any more. And I’d like to try to find another butterfly to replace the one I lost, but then I’m just going to worry about the same thing until he grows up too. I guess I could go get some netting or something to block off the rock shelf for a while, but it sounds like a pain, and an eyesore. And there will always be new fish spawning, so it’s not like it just temporary until the koi I have get bigger. Has anybody else had this issue? Maybe I just didn’t spend as much time stacking rocks this year when I rebuilt the pond as I did the first time, I left too many big gaps.