By the fourth month, much to our surprise, a female was brooding in both tanks and a few fry were visible within the rockwork. They did not survive the first week and were most likely lost to predation. One of the males was sold and attempts to integrate the second female into the main tank failed.
Specifically, immediately upon introduction, a fierce battle was waged between the new female and the resident male. This was clearly a fight to the death so the resident male was moved to allow the female to acclimate to her new surroundings. The female in hiding plead no contest and remained in hiding. One week later, the male was reintroduced with the same results, so drastic rearrangement of the aquarium landscape was necessary.
Eventually the male took his usual position in the center of the tank and bred with the female. However he became intolerable of the mouth brooding female and she was moved into a nursery tank where she released a dozen fry (shown middle). In the end, she died from the male's aggression when she was moved back into the main tank. The second female was more submissive and survived breeding with the male by constantly hiding in a well-concealed cave (shown bottom). She lived this was for a few more months before she was inevitably killed by the male.
In summary,? a colony will eventually turn into a colony of one, if there are not enough individuals starting off. In addition, adding other individuals later on is very difficult. As with other aggressive Malawian Mbuna, such as Cynotilapia afra, Melanochromis species and of course other Pseudotropheus species, hyperdensity or overcrowding is highly recommended to maintain harmony within the population and P. demasoni are no exception. Hyperdensity prevents the establishment of territories by forcing all fish, both male and female, to constantly fight each other, therefore preventing the succession of a single dominate fish.
