The Regal Demoiselle, a planktivorous damselfish native to reefs of the Indo-West Pacific, was first found in the Atlantic on reefs at Coatzacoalcos in the southwest Gulf of Mexico in 2013. In 2014 it was observed on reefs in the MPA adjacent to Veracruz city, ~150 km from the Coatzacoalcos reefs. In 2017 a retired mexican naval ship was sunk as an artificial reef in that MPA. Within 10 days of that sinking numerous pelagic recruits of this damselfish were found on that wreck, and a population was established on the ship within six months of that event. This video describes this rapid colonization and establishment and discusses factors that might have affected recruitment of this species to that wreck, the significance of the absence of native planktivorous damselfishes on that ship and their presence on a much older wreck nearby in the MPA, the usage of habitat by N. cyanomos on that ship & its apparent ability to use an empty habitat niche that native relatives do not use, and the significance of its habitat usage on that ship for understanding how this species might have been transported on mobile offshore-oilfield infrastructure from the Indo-West Pacific to the Gulf of Mexico. Published October 24, 2019 at Zenodo Repository: http://doi.org/10.5281/Zenodo.3518320. Also viewable on Youtube at: https://youtu.be/nd1Vg2U83q0 Sources of information cited in the video: 1 González-Gándara C, de la Cruz-Francisco V (2014) BioInvasions Records 3:49–52. 2 https://nas.er.usgs.gov/queries/FactSheet.aspx?SpeciesID=2936 3 http://doi.org/10.5281/zenodo.3364568 4 http://doi.org/10.5281/zenodo.44898 5 https://doi.org/10.1016/j.ocecoaman.2018.03.012 6 https://www.youtube.com/watch?v=CwuVfcOLQnI 7 https://www.youtube.com/watch?v=AjzTM0V_FgA 8 https://www.youtube.com/watch?v=yOM2oiR40_s 9 https://www.youtube.com/watch?v=hLg3rjBjySE) 10 Barth P et. al. (2015) Vie et Milieu 65: 91-100 11 DOI: 10.1016/S0065-2881(06)51003-X 12 Leis JM (2004) Marine & Freshwater Behavior & Physiology. 37: 65-88. 13 DOI 10.1007/s00227-007-0794-x 14 doi:10.1371/ journal.pone.0042672. 15 https://doi.org/10.3389/fmars.2018.00254 16 Leis JM, Carson-Ewart BM (2003) Marine Ecology Progress Series 252: 239-253. 17 https://doi.org/10.7717/peerj.4328 18 https://www.youtube.com/watch?v=xvtLgPEFwHc 19 https://en.wikipedia.org/wiki/Moon_pool