I think in those cases that the fish may have been ripe for the disease and the change in food was the final stressor that brought it on. Possible they may also have overfed. Easy to do with NLS. Allowing trophs to gorge themselves on any new food is risky business. I think the reason it's never been nailed down to a single cause is that there is no single cause, just multiple stressors which weaken defenses and allow naturally occurring intestinal bacteria and parasites to multiply unchecked. JMHO.I know of people who wont use NLS on their Tropheus because they got their first cases of Bloat when using this food and the change in diet is the only thing they have changed in there routine while keeping Tropheus.