Need more info.
Is this the only fish in the tank or are there other Africans in with it? If there are other Africans in the tank, they may have killed them.
How long have you had these fish? Sometimes it can take up to 3 weeks to see signs of illness from new acquisitions which is why it is best to quarantine any new arrivals for at least 3 weeks. If you just got them this could be stress related illness from the trip home, too.
How long have you had the tank? Africans can be really touchy about water quality. If your tank is new and hasn't cycled yet then that may be the culprit.