The liner will be just fine normally even if it freezes solid as the liner can flex with the pressure as long as there is not a sharp rock under that the ice can push the liner around the rock to the point where the rock can push through it. The problem with the stock tank is the drain in the tank. What happens is as the water in the stock tank freezes it slides up as it does in an ice cube tray. But a stock tank has a drain in it and this locks the ice so that it can't slide up and that puts a lot of pressure on the drain and the bottom until something gives usually the bottom. Mike

Just my 2 cents, but if you don't circulate the water some way (via pump), you will have a stagnant pool of water. Plants and fish in particular need circulating water. Your size is good for maybe 12 goldfish or comets, no koi. Remember - they WILL reproduce like rabbits. In a year you will have 30 or 40 - think ahead about were the offspring will go :) And rethink the plant shelf if you may have any predator problems - shelves are easy spots for cats, racoons and herons to hunt from - you might consider straight sides - 3' depth - and use other means (dark 'milk crates', pots, etc) to put plants where you desire. One other consideration - a 'hybid' or anything above ground would be safer if in your front yard where any unattended toddler could fall in.... :(

Hi Have never gardened anywhere but in s.florida so probably can't add much advice, though I've kept ponds since the early 70's. Preforms are way too expensive for what you're getting and if not supported perfectly will crack. Way too shallow for any kind of temp moderation,or predator protection. Could one of these make it through a zone 4 winter?? Planning to drain during the winter?? I think if I lived in your climate I'd definitely go with a lined pool at least a foot below frost line. One trick I've learned with herons if it's too deep to wade they won't fish and even if they do the fish are MUCH harder to catch. Of course if you make it over 3 feet deep preventing wading by even great whites, you will attract diving birds lol I get Anhingas but I don't think they occur in your area?? My worst are night herons they have caught more fish than all others combined lol. Deeper water right up to the edge also slows down raccoons and turtles but seems to be VERY attractive to swimming dogs lol and kids.lol My approach has been to keep fish that breed so fast there are plenty left for predators lol. I love my water gardens in spite of all the problems but I think if I had to contend with winter I'd keep a large aquarium lol. Can't imagine the hassle of contending with the seasons .I'm WAAYYY too lazy for that. Good luck with whatever you decide. gary

Hi there I am new on here but have found the info valuable so far so thanks to all. I think we have just made a HUGE mistake with our new pond. We originally dug a pond 6ft by 9 ft by 2ft deep and kept seven goldfish in it which wintered well and seemed happy. Being bitten by the fishkeeping bug we then dug a larger pond on the raised area above the original pond which is 15ft by 20ft but we miscalculated the depth. We originally planned 2ft 6" but when it was filled we realised it was less than two feet deep. By this time we had moved the fish into place and have been given two smalll koi and three Golden orfe along with another bucket full of goldfish so 29 in all. The water surface is plentiful but i am worried about the lack of depth. We have a large rubber liner in it which is now trimmed to size and rocked over and planted out around the edges. so to change this would mean a complete redig. Has anybody any ideas whereas we could cut the middle out of the liner and dig the middle bit a lot deeper then join on a new piece of liner? I think this could be an option. I dont want unhappy fish but my husband is groaning at the thought of rebuilding the whole thing.!