Make sure it's slate and not shale. Shale leaches an oily substance that
would be toxic to the fish.

The only way I could "sign on" to (even large) rocks on the bottom would be
if they were permanently mounted, i.e., cemented in place. That way, there's
no place for the crud to get caught. However, it would still get overgrown
with algae, so you wouldn't see it anyhow, so why go to the trouble?
Lee

"Mike (mixmanx at AV and DVD Forums)"
wrote in message
...

"LeeAnne" wrote in message
...
I also would agree w/the masses here and say 'no' to gravel. What I did
was
put some flat rocks in - I was able to purchase them at my local garden
supply place by the pound. I was calling it slate until I learned it
was
just flat cut field stone :-)

That's not a bad idea, using slate I mean, there is a water garden centre
near me that sells nice big flat pieces that I could arrange into a simple
flat base.