The video shows a spawning pair of Pseudosimochromis curvifrons. This species isn't exactly rare in Lake Tanganyika, there just isn't much demand in the hobby so they aren't collected. They are rumored to be very aggressive but without more hobbyists keeping them, its hard to say if they are any more aggressive that Simochromis, Tropheus or Petrochromis. There are some colonies in the U.S. and occasionally they appear for sale, but they are few and far between. From what I've seen, they are often kept with Tropheus and share the same diet.