I have a 55 Gallon tank I'd like to re-create to focus on the Pseudotropheus Crabro (Bumblebee/Hornet Cichlid).

This is the idea I have now. I want to use slate to create tons of caves, tunnels, and flat rocks for them. I currently have gravel, but think they would enjoy sand better. Using the slate, I want to create like a second layer.... so half of my tank (like the left half) would actually have another "bottom" with substrate about half way up. This splitting makes me think I should stick with gravel, as I believe sand would fall off.. ?

I'd like to kinda re-create their natural environment. I guess my main ques tion is.... what kind of catfish can I get that I will have the most likely success rate of spawning and living in peace with the Bumblebees? I understand in the wild the bumblebee will guard catfish and even pick off parasites. Upon catfish spawning, they change to their more aggressive black color and eat the eggs. I want to create that.

I have a feeling 55G might just be too small to accomplish this...

This is the basic basic idea of slate work. I think I want to keep the driftwood where it is and build around/on top of..

<img src="http://onfinite.com/libraries/1470037/944.jpg" />

This is the inspiration for the right side of my tank, but on a smaller scale...

<img src="http://www.aquahobby.com/tanks/img/801_Mike_1.jpg" />