GiveMeABMW wrote:

I know the rule is 10g per goldfish, but does this hold true when they
get to be 8-12" long? How many gallons do they need then?

At least 3 gal / inch.

I'd be talking with the wife about "needing" a pond.

-D
--
"Faced with the choice between changing one's mind and proving
that there is no need to do so, almost everyone gets busy on the
proof." -Galbraith's Law