ruben is right, variety is the best.
Look for:
New Life Spectrum Cichlid Pellets
Hikari Gold, Hikari Staple, Hikari Excel
Give them Algae wafers every once and awhile (as stated before)
Also: Spirulina Enhanced Brine Shrimp, Beefheart, and the OCCASIONAL bloodworm.
For a live treat try ghost shrimp, or the occasional feeder guppy.
Also veggies can be a good idea.