Above Ground pools still need a fish safe pond liner. Another option is vinyl/rubber ponds which is usually found at farm supply stores.
Here's a couple of links for you to check out
http://www.barnworld.com/sa/c/Dura_Life_Polyethylene_Stock_Tank.htm
http://www.aquaticeco.com/subcategories/953/Portable-Tanks
Here's a couple of links for you to check out
http://www.barnworld.com/sa/c/Dura_Life_Polyethylene_Stock_Tank.htm
http://www.aquaticeco.com/subcategories/953/Portable-Tanks