Centropyge nox is found at depths between.5th This species is common in the coral dense parts of the outer reef slopes, although it is occasionally recorded from lagoon areas and channels. The midnight angelfish shows a preference for habitats which include dense and varied growth of benthic invertebrates. It is typically encountered as solitary fishes or as pairs. This is a herbivorous species which feeds on algae. The live in harems of 3-7 fishes.