They may actually be brooding already. I've been breeding Heros sp. "Atabapo", which is probably just a population of severus IMO. They always pick up the eggs within 24 hours of being laid and brood them for several weeks. The parents take turns so that one gets a chance to eat while the other is holding. Holding isn't especially obvious with these fish, either. Do both eat at the same time when you feed? Or does one eat while the other acts like it is eating without opening the mouth? Is the orange throat more obvious on one fish?
I know a lot of people who expect them to have a big bulging chin like Mbuna or Haps, and they just don't show it that well. The fry are very small, and even a considerable number can be held without showing much more than a slight increase in the orange membrane beneath the chin. I thought mine had eaten one spawn, and suddenly one day I look in the tank and there was a cloud of fry around them - SIX WEEKS after they had spawned! Of course, they may have been releasing them when I wasn't present, as the tank is in the basement, and I hadn't been getting down there as often as I should.
I know a lot of people who expect them to have a big bulging chin like Mbuna or Haps, and they just don't show it that well. The fry are very small, and even a considerable number can be held without showing much more than a slight increase in the orange membrane beneath the chin. I thought mine had eaten one spawn, and suddenly one day I look in the tank and there was a cloud of fry around them - SIX WEEKS after they had spawned! Of course, they may have been releasing them when I wasn't present, as the tank is in the basement, and I hadn't been getting down there as often as I should.