Rock structure in tank

Question
I recently upgraded to a 45 gallon tank.  I didn't place egg create underneath the gravel because I wasn't aware that you should do this to help even out the weight.  I currently have the bottom quarter of the tank covered with rock and would like to increase the amount of hiding space.  I currently have on small pleco, 1 three inch catfish (name escapes me but comes from the same lake), a 6 inch yellow lab, a three inch red zebra and two Nicaraguan cichlids that are an inch long (the pet store lied and told me they were compatible with African cichlids...but they are doing fine).  I would like to increase the structure to keep the aggression under control.  Thanks in advance.

Answer
Hi Amber,
I can bet that your unknown catfish are likely a synodontis species. ;)

I think this website and articles will help explain the fundamentals of african cichlid tank setup and rock structure in the tank better than I can ever explain.

http://cichlid-forum.com/articles/aquarium_setup_list.php

I hope this helps!
Karen~