Gravel/ Sand

[shrimply]

I just wondered if you are supposed to flatten out the gravel after the cichlids have dug it out. Or do you leave it alone both my piles of rocks now have tunnels right under them.

 

[freddyk]

The fish shouldn't be able to tunnel under the rocks - the rocks should be placed directly on the bottome of the tank and then the substrate put in. If you allow the foundation to become unstable you could get a potentially catastrophic collapse, especially if you use a lot of rocks. Otherwise it doesn't matter whether you flatten the substrate, whatever floats your boat.