Loisellei are a very nice looking fish. They are the least aggressive of all the Parachromis. Though it will stand up for itself if fronted, but does not seek out a fight. I have all of the para, and my RTM's dont like any other fish near them, the Freddies are territorial, the jags dont like any one near them either. And the Dovi, well is by itself with his mate.
My male Loisellei is 10" and his female 5". The male and my Hoga are the alpha males in the tank. They flare once in a while at each other, but thats it. My Hoga's have even spawned right next to the Loisellei's home, and the loisellei leaves the spawn alone, and the Hoga's ignore them. Its like they have a mutual understanding. Now if I had my Jag or my RTM in that tank. There would definitely be some fighting.