Tannins have antibacterial properties but are found nowhere in the rift lakes so aren’t helpful for a fish that has no adaptations for them.
Personally I would stock more at a time simply because mbunas establish fast and once in the tank with no one else, it won’t be happy with the introduction of others and can cause issues aggression wise.
Personally I would stock more at a time simply because mbunas establish fast and once in the tank with no one else, it won’t be happy with the introduction of others and can cause issues aggression wise.