Min pond size for 10 goldfish?

Dont know what tires means but but on step 5 it shows a pic of the shelf.
 
So if I dig a hole with the length of 9ft with- 8ft, max depth- 3,ft average- 3ft The liner size should be -18ft x 19. Is that right.
 
Don't bother getting a preformed pond. IMO, they're overpriced. If you're looking for a great deal, try buying a cheap pool. Heres a 2500g pool I found at wal-mart.com

http://www.walmart.com/catalog/product.do?product_id=5693282

Im not exactly sure if its fish safe, but I'm pretty sure it is.

Just don't use the filter that came with it.
I would not consider using a 'cheap pool' for any fish. They are not made for fish and it will not last long.
I agree with DangerDoll on this.
 
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