Scott - the fat content of that food is rather high, at least for mbuna. As a general rule you want to stay under 10% crude fat. The crude protein content of NLS Cichlid Formula is 34%, crude fat 5%.
Protein itself does not cause bloat, unless that protein is overly difficult for the fish to digest. (such as grains & grain by-products)
I've raised numerous juvenile mbuna on diets consisting of 50% crude protein, and have never once fed any of my mbuna veggies of any type. That would include some of the most herbivorous species of mbuna in the lake, such as Tropheops macrophthalmus. IMO the vast majority of 'bloat' cases involving mbuna are not caused by dietary issues, but by other forms of stress which cause an unhealthy environment for the fish, weakening their immune systems. All it takes is one weak fish to get sick, and your entire tank can start to go south within a few days.
This is something that requires treatment immediately, or it can spread like wildfire.
Also, 'bloat' is not a disease, it is but a symptom, and usually when one sees a bloated fish it's in the final stages of the disease. What you are most likely experiencing is spironucleus.
http://www.cichlid-forum.com/articles/spironucleus.php
At this point I think that treating with Jungle Parasite Clear or Clout would be the way to go. When stress levels increase in cichlids it's usually followed by an increase in intestinal flagellates. You need to treat the entire tank in order to destroy any/all potential pathogens present. Spironucleus can be transmitted via contaminated fecal matter, so you must treat the entire tank, and not just remove the fish that already are showing symptoms.
The following quote is from Ad Konings "Back to Nature Guide" to Malawi Cichlids 2nd. edition.
"Malawi Bloat is believed to be caused by a flagellate (a unicellular animal, a protozoan). This flagellate occurs in the intestines of all Malawi cichlids but normally causes no harm since the fish's immune system can cope with it. However, in a stressful situation such a balance may disappear and the fish may lose its resistance against an outbreak of a flagellate "attack". This often leads to bloat."
..... which is along the exact same lines as what the authors in the link above state about spironucleus.
In simple terms, in 'healthy discus' S. vortens is commonly found in the flagellated stage in the lumen of the upper intestine, where it remains, controlled by the immune system of the fish. In stressed discus, the immune system is placed under greater strain, and the organism, in theory, multiplies unchecked causing considerable localised damage. Once the damage is severe enough the intestinal lining is penetrated and the S. vortens enters the blood causing systemic and organ infections.
HTH
