Ctenactis is a genus of solitary disc corals in the family Fungiidae. Members of this genus are found in the Indo-Pacific region.
Members of this genus are medium to large oval disc corals. They have an axial furrow with usually a single mouth opening, though sometimes there are several mouths. The septa are heavily toothed with sharp triangular teeth. The costae are weakly developed and have long arborescent spines.[citation needed]