Demasoni are like tropheus. Large colonies to spread around the hate. Even in my 75 I have a hard time with 4 males. All was fine for over a year and breeding was taking place. Then one day BAM! The colony decided not to accept one male and tore him to shreds. In a smaller group this will happen faster. Probably even before maturity and breeding occurs. To the poster with the 29 - I hope you are putting them in a larger tank and making a colony, otherwise you will have a tank of one demasoni.