My guess: Ciguatera - extreme cases causes sodium channel depolarization that can cause paralysis and heart contraction.
A close friend died from a heart attack after getting it eating at an island resort in PNG.
My Co-Driver got from a "5 star" hotel restaurant right here in Oz, now tropical reef fish are avoided, as once inflicted you will have a lower threshold. Indeed relapses can be triggered by odd things like in my co-driver's case 30 years after, bleach fumes, alcohol, and sea scallops [a cold water shellfish].
Not sure about Bali issue - anytime one eats reef fish, be it Mel/Syd/Bne/Pth/Cns/Dps you could run a risk.
One thing to note though chikungunya [mosquito virus similar to dengue] is on the rise in WA FIFO mining communities. Its origins are Indonesian. But then Oz has tropical Dengue and Ross River - Safe in the South well no Barmah Forest virus is rife in Murray River region.
