【Background】With assistance by the Food and Agriculture Organization of the United Nations (FAO), tilapia were introduced into more than 85 countries of the world. In 1956, tilapia was introduced to China, and tilapia production increased to million tones in 2006. Aside from its value as an important aquaculture species, the tilapia is sometimes problematic to native fish. 【Method】 We observed the early development of the Nile tilapia, and its predation on native fish. Additionally, we analyzed the distribution of Nile tilapia in the Pearl River using the data from fishery investigations and other literature. 【Result】Nile tilapia larvae develop quickly, with sufficient yolk nutrition. Tilapia fry can prey on native fish larvae. It is clear that Nile tilapia have spread throughout the length of the Pearl River, and is very common in some sections. 【Conclusion and significance】As native fishes are being threatened by the tilapia, it should be regarded as a dangerous invader in China.