You have a couple options, both somewhat DIY related. You could pick up a fiberglass barrel from lowes, and patch the hole. They probably have some sort of old school sink plug that will fit the hole (think rubber bathtub plug, with a rusty chain attached, in your grandmothers claw footed tub) If they don't have a plug that will fit, you can fabricate one with a little duct tape and silcone.
If you don't want to mess with a pond liner to go into a "real" wine barrel, then you can coat the inside with waterproof two part epoxy. No tannins. Period. Just look up a how to on building a plywood aquarium. There are various how-tos on youtube for that sort of thing, that will show you the process of epoxy coating wood.
Hope this helps!
As a matter of fact, yes, I always post, or reply, in novels. I'm adding it to my signature because it seems like I say it in every post!
Fraternity of dirt #32 I'm dirty
DIY Asian themed aquarium stand