RD> Me too!  What kind do you have?  And have you foun anyway to keep them 
from
RD> uncovering the undergravel filter?
In a word, no.  No mater what you do to landscape the tank, ciclids will have 
other plans, and WIULL rearangew things to suit themselves.
Advice?  Ditch the undergravels in favor of power filters.  bio-mechanical 
filter such as the Wisper line do a nice job, and the Wispers "waterfall" 
return breaks the surface tension for good gas excange.
You will never stop the fish from diging, so you might as well accomidate 
them.
    --Phoenix--      Rising Above the Flames
---------------