The Redbelly Tilapia (Tilapia zillii, also classified as Coptodon zillii), known locally as තිලාපියා (Tilapia), is an introduced freshwater cichlid species in Sri Lanka belonging to the family Cichlidae. Originating from Africa and the Middle East, it was introduced to Sri Lankan freshwater bodies—including reservoirs, irrigation tanks, and slow-moving rivers—primarily for aquaculture and vegetation control. It features a laterally compressed, robust body with a single continuous dorsal fin supported by strong anterior spines, a pale pinkish-to-red chest, and olive-brown flanks crossed by subtle vertical dark bars. Unlike mouthbrooding tilapias, this species is a substrate spawner; both parents dig shallow depressions to lay and aggressively protect their sticky eggs and fry. Exceptionally hardy and tolerant of wide temperature and salinity ranges, this omnivorous feeder consumes large amounts of aquatic vegetation, algae, and benthic invertebrates, often outcompeting native fish species in modified aquatic ecosystems.