steve wrote:I tried the 2 little fishies aquarium epoxy on my ceramic tiles and it didn't hold well. If you find out more about that JB Weld stuff, let us know

Well, I manage to contact the manufacturer of JB Weld asking them if their product was aquarium safe and they replied yes, it is non-toxic.
Here's their website. They also have a lot of technical data (MSDS) on all of their products....
http://jbweld.net/index.php
This stuff is extremely strong and durable. It can be used for everything from china to engine blocks. It is also permanent. If used correctly, any bonds you make cannot be undone! The only thing I don't like about this stuff is when it cures, it is a dull grey color. somewhere on the website they state that they are working on a clear formulation.
It's sold in most hardware stores.