Does he run dart accross the aquarium somewhat erratically? Does the white stuff look like cotton-like tufts? Where is the white stuff, over the mouth, eyes..skin? If it is, then it is fungal infection.
Another very common cichlid disease is Ich or Ichtyophthirius. They start with this white salt-like marks that appear on the head first, and then spread over the whole body. Normally the breathing is quick, the fish scratches a lot, and the eyes and fins, both, become cloudy.
If it is, then I suggest to turning the water temperature up to 85-88. The cichlids dislike warm water. Add air stones for added aeration. Along with the temperature change and added aeration, I usually add about one teaspoon of canning and pickling salt per gallon of the water to help the fish recover from the stress caused by the disease by reducing osmotic pressure, enabling the fish's own immune system to fight back. Salt is also harmful to ich.
You can read this article about Ich.
Ich: An Old Cure for an Old Disease
or go to this site to research on other fish diseases, it should give you a description of them as well.
I hope I helped!