I use the metal ones...and like them very much. I do have one poly tank. I drain it during the winter because the oval ones seem to freeze down farthur than the round ones. I had a 3 1/2 foot round tank freeze nearly solid because I hadn't plugged in my tank heater yet when the wind chill went down to -30*.

Mamasue, so the galvanized ones work ok, huh? How long have youbeen using the metal ones?

I've had a metal round one for around 7-8 years and just noticed a hole in the side today. Usually just have water lilies and mosquito fish in it but right now, the koi and goldfish are in it until I separate into their normal ponds, a 9' round poly stock tank for the goldfish and a 4x10 lined wooden trough for the koi.

I have always used the galvanized tanks. I have two very large ones that were used when I got them. They had pin holes in the bottoms but my husband soldered them all up and then he sprays the bottoms with the spray on rubberized undercoating that you can buy at auto parts stores. That seems to work pretty well to help them last. I have had people tell me that doing this will only make them rust out faster but so far that has not been the case. The two tanks have been going for almost 3 years now and they have not sprung any leaks. I don't like the look of the poly tanks and don't really want to spend that much buying landscape blocks or something to cover it up. I spray painted the outside of my galvanized tanks a light tan/dirt color and they blend into the area better. The galvanized tanks will eventually spring leaks but if you can fix them yourself its not that big of deal. The poly tanks may or may not last longer, it just depends. Sometimes they will crack if the tank isn't real level and the weight of the water isn't even. Sometimes they will crack if something hits them pretty hard, such as a rock thrown by a lawnmower.

I have had a galvanized tank (300g)in the ground for 10 years without any issues. I'm a zone 3 so it freezes every winter and still goes strong. Doesn't even sport any rust spots.

Wonderful news! Hey Cathy, I remembered you used stock tanks but didn't know what kind. I really miss my big yard and ponds but not the maintenance. Getting too old and it began to worry me.
Starting over is kind of fun. I know I have to have a water feature to be happy and the above ground stock tank would work best. I'm going for the galvanized metal because it is the right shape and the guy @ Tractor supply said the rubber ones do crack and split. Because it will be a small pond, if I have to redo the whole thing, it won't be the chore it was to replace a liner in my big ponds (which I did 2 x's :))
Thanks for all the advice. I'll post pics when I get it done!

Hi Pat,
What size are you going to get? I've seen people use them for ponds in the size that's something like 6'x2' and also the 8' round one.
I know what you mean about the maintenance. Its just wearing me out, and doesn't bring pleasure when its so much work. I've limited some of the stuff I do, but I sure get "the fever" in the spring, to over-do, so I'm trying to keep that under control.
I love my above-ground tanks. I've had them for years, and haven't even used a pump in them and they stay pretty clear. I have 2 300 gal Rubbermaid above ground and keep a water lily and a couple marginals in each. I enjoy them alot. Good luck to you!

I just answered a similar question over on Cherifree's post about using galvanized stock tanks, so maybe that would help you? In a nutshell, I've used them for years and haven't had any problems with them. I got the idea for using them as ponds after keeping them for livestock for even more years without problems. I've had them last ten years or more before rusting through. Can't say the same about the rubbermaid tanks.

Hi, I buying a 8ft X 2Ft metal stock pond new for my above ground pond. My koi have outgrown the one that I made three years ago. I was thinking about spraying the stock pond with a rubberized black liner of some sort. Has this ever been done? If so, what product recommendations are out there that won't kill my fish or beautiful plants????? Help please.

Question.....I have a 9' 1000 gal. blue poly tank I sunk about 8" into the ground. I'm in zone 5 & am indecisive whether to leave about 8" of water in it over winter or completely drain. It is an adult kiddie pool/dog pool that I will be tarping over regardless. Thoughts on this are appreciated