The problem with tilapia occurs when it is released into ecosystems where endemic species are not prepared to coexist or fight to survive. The Red Nile Tilapia adapts and reproduces quickly, so controlling them or expelling them from a free habitat is complicated, time-consuming, and expensive. The impact of any introduction varies according to the geographical region and the specific ecosystem. Generally, given its resistance, voracity, and high growth rate, tilapia easily becomes a competitor to other fish species.
Tilapia are responsible for severe ecological impacts in natural environments, such as the displacement of native species in the river to other bodies of water like seas and oceans. Likewise, as an exotic species, it is invasive in developing countries. Additionally, their treatment has also been changing them over the last 20 years. In the catalog of exotic and transplanted aquatic biodiversity in Colombia, Oreochromis niloticus is considered a high-risk species, giving it a score of 1056 out of a maximum value of 1500 points (Gutiérrez et al., 2010 cited by Gutiérrez & Lasso, 2012).
In addition, Australia has indicated that the Red Nile Tilapia is an extreme risk in the risk analysis of introduced exotic fish species, giving it a rating of 23 (out of 24) points (Bomford & Glover, 2004). Other countries that have also reported the Red Nile Tilapia as an invasive species are Bangladesh, Japan, Peru, the Philippines, India, Taiwan, Thailand, Japan, and the United States (Global Invasive Species Database, 2012c).