He won't need any tankmates to go with these trouts. They'll terrorise anything that doesn't get up to their size (about a foot+). I'm praying that he gets a good proportion of females or else when they get up to sexual maturity, all hell's going to break loose. Hmmm... come to think of it, Dom, a trio (1m/2f) of Fossochromis Rostratus would look nice in that tank with all that yummy sand... (Rosties are Malawi sand sifters)