True red devil or imposter?

[RD.]

Not exactly. The body types, including larger fleshy lips found among the Amphilophus that are found in the crater lakes, is further explained in great detail in the following past discussion.

A. cf. citrinellus - A potential case of F1 Midevils? | MonsterFishKeepers.com

In the first paper linked to below they mention A. citrinellus types with elongated bodies, and some with thick lips. This seems to be a reoccurring pattern among the various studies performed over the past few years. While A. labiatus has morphed (longer head, compressed body, and fleshy lips) due to it's specialized feeding technique of feeding on invertebrates and crustaceans found within the rock crannies, apparently some of the A. citrinellus types share some of these same physical characteristics.

Big lips does not necessarily = A. labiatus, especially in an aquarium strain