whoa!! tread with caution.
i have an extreme love/hate relationship with p. demasoni.
on one side, they are a gorgeous fish and also stay relatively small.
on the other, i have NEVER been able to keep them from systematically removing all of their kin from my tanks...
.
i had my 125 set-up for mbuna with yellow labs, rusties, zebras, and i had 12 demasoni--b/c i was told that you either want to keep 1 or MANY to keep them from killing each other.
the MANY idea did not work well for me. i got a male starting to mature and he would take out about 2 a week until i was left with only him.
your mileage may vary, but i would only keep a single specimen if i did them again.
M