2) Long term exposure to poor water quality.
parasites will be getting the uppperhand. Malawi's are very capable of fighting
of decises, but when the conditions in the aquarium are poor they will have a
lot of problems with it.
3) A bad diet, Malawi's have their own dietery needs, you can's give a cichlids
that lives on algae to much of protien food like bloodworms. Also to be avoided
is the use of only flake or pelletfood they contain a lot of fishmeal.