I don't think this is a Nimbochromis (which are large predatory fishes). This colour pattern is called Orange Blotch or OB and quite a few Malawi cichlids have an OB morph as well as a normal one (sometimes called BB). To complicate matters further OB females are much commoner than OB males, in which the body also has a bluish sheen when the fish is mature: the fish in the photo shows some sign of this. These OB males are called 'marmalade cats' (don't ask me why ).
From the general conformation of this fish, I don't think it's a Labeotropheus or Maylandia species, where OB specimens are fairly common. It might be a species of Pseudotropheus or it might belong to a different genus altogether. You have passed the limits of my knowledge about Malawis
