The Indo-west Pacific damselfish Neopomacentrus cyanomos was first recorded in the West Atlantic in 2013, when it was found to be common on reefs near Coatzacoalcos, in the extreme southwest corner Gulf of Mexico. During 2014-2015, this species also was found on reefs farther afield in that area, but not in the northwest Gulf, nor the north-eastern tip of the Yucatan peninsula. These data, and information from public databases on invasive reef fishes, indicate that N. cyanomos currently is widely distributed in, but restricted to, the southwest Gulf of Mexico.

 

Mitochondrial DNA barcodes of N. cyanomos from that area match to those for this species from its natural range, but do not indicate the ultimate origin of the Gulf of Mexico fish. Possible modes of introduction to the Gulf of Mexico and the potential for its further spread with negative effects on the native reef-fish fauna are discussed, and directions for future research suggested.