This type of sudden death, the bloated look, wide open mouth and flared gills
is something that has happened to many of the dozen C. compressiceps I had over this past year apears identical to the same thing that frequently occurs among Apistogramma.
Onset of symptoms is sudden. Often associated with fish that apparently had good appetites and interest in life, courting and normal territorial defense, then overnight or even just turning away fromthe tank and back the fish is dead or dying. Not like an epidemic, it can happen over a long period of time among different apparently healthy fish and tanks.
Autopsies don't show much more than you already can see, puffed up dead fish that was apparently fine shortly before. Maybe even better than fine, showing excellent color shortly before death..
It seems to have a slight correlation with a heavy feeding often on live blackworms or frozen bloodworms but it doesn't seem to be so much as what was eaten as it does with gorging. I don't think that is the cause. I suspect that it has to do with a few differnt known disease organisms but they are also just very common bacteria especially often found in abndance with any dead fish. Aereomonas, Pseudoareomonas ands Vibrio species are commonly found but I think it would be jumping to conclusions to assign the cause of death to these organisms. The deaths have also quickly followed a normal water change.
I do no have any experience with Rift Lake Cichlids and the so callled Malawi Bloat but it sure sounds very similar
I guess my point is mainly that if we are going keep these Cichlids, we are going to loose some fish this way and it may not have much to do with our care or lack thereof and until more is understood we should not be too quick to accept the blame. Just understand it may be an omnipresent risk we run as long as we keep these Cichlids and the cause and any treatments are unknown and ineffective.
The need for better understanding is great and we can hope that we will learn more eventually.