Invasive species, such as tilapia and carp, negatively impact wild axolotls through competition, predation, and the spread of disease.
Fishing is important to the local economy of the axolotl where approximately 80 fishermen reside. Non-native Asian carp and African tilapia have replaced the axolotl as the main catch, and as such, introduced fishes have increased to high abundances and have impacted wild axolotls through competition and predation. A recent study collected 600 kilograms of tilapia in one small channel using a 100 meter net.
The axolotls are also being affected by disease, probably spread by invasive species, and as a result of poor water quality.
Sources: (Griffiths, et al., 2004; Majchrzak, 2004; Zambrano, et al., 2010)