Would be nice but I don't think the rubberized stuff is available. But I will keep in mind the stucco technique as it might prove beneficial it I can get it so it wont crack under weight. there are some treated lumbers here. Very expensive though. we are talking twice to three times as much as you would buy it for in the States.

I would be great to find some rubberized coating that is safe for fish or like he said coat it with sweet water boat/hull paint or non toxic swimming pool paint.