Sustainable material for waterproofing the fish tank.

[arnoldboer]

I'm looking for a very sustainable material to make a waterproof fish tank. The structural part could be made of wood. But how to waterproof it? I don't like plastics because all the chemicals involved in the production of it and the possibility of leaking those into the fish tank. There are a few which I can think of, but they all have major disadvantages:
- Glass, breakable, costs a lot of energy to produce
- Lining with clay, probably not 100% waterproof, deteriorates the wood.
- Painting with linseed oil, what does the oil do to the fish? Does the wood deteriorate?

I am capable of doing a LCA (Life Cycle Analysis) in the end. But first I need some great ideas. Please help me in my search and I'll be happy to share my results with you!

Regards,

Arnold Boer

[urbanfarmer]

Make a liner out of latex. Behold: http://sarawak-rubbertapper.tripod.com/process.htm