The presence of the zebrette goby (Tigrigobius zebrellus) is reported for the first time in the Canary Islands, as well as in the eastern Atlantic. A new established colony around the floating docks of the Marina Santa Cruz de Tenerife harbour has been studied. Over two hundred individuals at different developmental stages have been counted. Its restricted distribution and population characteristic show that it has an established population but with no evidence of expansion to its vicinity. Our study indicates that the population of this exotic species could be easily eradicated to avoid any possible negative impact on local benthic communities. However, if such measures are not soon implemented by the local government this study can also be used as the early invasion stage of an exotic fish species across the Canary Islands.