It sounds like you have a nice tank going!
In your case, if you feed protien rich foods you are going to have more issues. I suggest you cater to the vegitarians, and feed primarily green foods filled with more plant content, rather then fish meal. For treats once in a while, maybe once a week of your current cichlid protein. Variety is always best, you can feed them many veggies direct from the fridge. Frozen peas are always a favorite of mine, just a couple, and you will see quite the soccer game! Seaweed paper, zuchinni, many types of lettuce are also good. Remember just a little at first until they realize it is food and then you can give them a little more. In the wild, they are constantly grazing on the algae covered rocks, so let some green grow on the back of your tank so you can watch this natural behavior. On don't forget algae wafers too!!!