I just play it safe and feed them everything. Algae wafers, massivore pellets, bloodworms, cucumbers, and there is plenty of wood. Lol
For decades Tropheus keepers felt that due to the intestinal length & long digestive process in that species, it should only be fed low protein "green" food, and that any amount of animal based protein could cause bloat. Yet science has proven that in captive bred species of Tropheus the intestinal length can be half of what's found in wild specimens.
A more recent study that was published in 2009 demonstrates just how great intestinal plasticity can be in response to the diet quality of various species of fish found in Lake Tanganyika.
http://limnology.wisc.edu/personnel..._Functional-Ecology-LT-cichlid-gut-length.pdf
The above paper clearly demonstrates just how adaptive some species of fish can be when it comes to their diet. As long as one feeds a quality food, diet will generally be a non issue, and will not cause any type of major gastrointestinal stress. Most fish were born to adapt.