Would anyone know the answer to this one? :-? Yesterday I put into my new tank 4 Pseudotropheus Saulosi and 4 Pseudotropheus Acei (1m-3fm for both species,) these are the first occupants. I have been told that both are peaceful species and they are getting along incredibly well! However the male Saulosi is a juvenile and is changing colour I have noticed that his dark stripes can fade and then reappear within a matter of a minute, is this a reaction to the presence of the male Acei which seems to be a more mature fish, could this be submissive behaviour? Thanks all, Teddy.