I found a paint that i think might be safe for fish and is only 23 bucks a gallon. Its made to paint swimming pools and they have several different types of it. i was gunna get two gallons of it to paint my ply tank. let me know if anyone has used it or see's anything saying it shouldnt be used for this
http://www.insl-x.com/viewProd.asp?prodID=190
http://www.insl-x.com/viewProd.asp?prodID=190