Mesoheros festae is a medium-to-large cichlid with a robust, laterally compressed body. Its most striking feature is the bright red to orange coloration on its fins and along the flanks, particularly in dominant males or during breeding. The body base is usually olive-brown to gray, providing a contrast that makes the red coloration pop.

Males are larger and more vividly colored than females, with elongated fins and pronounced body markings. Adult size can reach 20–25 cm, making them impressive display fish for large aquariums.