My newly stocked 125g african cichlid tank had a dead fish. 20 2'' mixed africans and 2 2'' black convicts for the time being. One of the blue fish was dead im guessing a socolofi. Bought the fish last week so im hoping he was just sick. I don't think it was a convict because they are all the same size and convicts just been acting like the rest. do you think it was a result of another fish? or just sick.