Nile Tilapia

The Nile tilapia is a large, deep-bodied cichlid native to the Nile basin and freshwater systems across tropical and subtropical Africa. It belongs to the genus Oreochromis, a group of maternal mouthbrooding cichlids. Because of its fast growth, hardiness, and tolerance of varied water conditions, it has been introduced to freshwater systems on nearly every continent, making it one of the most widespread fish species on Earth. In many introduced ranges it is now considered invasive, competing with and displacing native fish. Wild populations remain most diverse within Africa's Rift Valley and Nile watershed lakes and rivers.

• Deep, oval, laterally compressed body
• Olive-gray to greenish-silver coloration, sometimes with a pinkish or golden tinge
• Distinct dark vertical bars crossing the caudal (tail) fin — a key diagnostic feature
• Long dorsal fin with a spiny anterior section and soft posterior section
• Faint vertical bars may appear on the body, especially when stressed or breeding
• Small, terminal mouth with thick lips

Adults reach 20-60 cm depending on environment. The barred tail fin distinguishes it from the Mozambique tilapia, which lacks strong tail banding and has a more uniformly brownish body.

Nile tilapia inhabit warm, still to slow-moving freshwater: rivers, lakes, ponds, canals, and reservoirs throughout tropical and subtropical Africa, with its core native range in the Nile River system and adjacent Rift Valley lakes. It tolerates a wide temperature range (roughly 8-42°C) but thrives best between 20-35°C, and can survive brief exposure to brackish water. It favors shallow, vegetated margins for feeding and nesting but ranges into open water as adults. Due to widespread aquaculture stocking and escapes, self-sustaining populations now occur far outside Africa in warm-climate freshwater systems worldwide.

Nile tilapia are diurnal, schooling omnivores that graze on phytoplankton, algae, detritus, and small invertebrates by filtering fine particles with specialized gill structures. Males establish and defend circular nest depressions in shallow substrate during breeding season, performing courtship displays to attract females. After spawning, the female collects fertilized eggs into her mouth and broods them until they hatch, continuing to shelter the fry in her mouth for days after hatching — a strategy called maternal mouthbrooding. This parental care contributes to high survival rates and rapid population growth, a major factor in the species' success as both a farmed fish and an invasive colonizer.