Trudy-
Don't be discouraged by the clay pot. . .It may be more suitable than
you realize. Three years ago, I decided to turn a large blue glazed
pot into a water garden, with gold fish, and water lilies. It had the
unfortunate hole in the bottom.
I used a method similar to what David provided, and also added a coat
of pond sealant to the inside of the pot (I chose a black colored
sealant). That pot is still out there on the patio with my fish and
water lilies doing just fine. . .Leak free;-)
However, another idea you may try, if you are squimish about the clay
pot, is a whiskey barrel with a hard plastic liner. Home Depot and
Lowes sells those hard plastic liners that fit nicely inside the
whiskey barrel.
Good luck!
Myrl Jeffcoat
http://www.myrljeffcoat.com