Resumo. Abstract Several fishes of the family Poeciliidae are commonly produced in ornamental aquaculture and also used for pest control, leading to their introduction in numerous countries. Many of these species exhibit tolerance and invasiveness, as exemplified by Xiphophorus maculatus (Günther, 1866). This report documents the presence of X. maculatus in a Caribbean coastal stream in Venezuela. Quizandal Creek has experienced significant human intervention in its lower drainage and channel area. In the final segment of the creek the fish were captured using hand nets and beach seines. The specimens were transported alive to the laboratory for evaluation and subsequently preserved according to standard methods and later were cataloged in the fish collection. 16 males ♂ and 8 females ♀ (16.6-29.4 mm SL. CPUCLA-3630) from the Quizandal Creek, part of the coastal drainage of the Borburata River, were analyzed. This is the first report on the occurrence of Xiphophorus maculatus in natural environments of Venezuela. These coastal streams are situated in a zoogeographic transition zone between regional freshwater ichthyofaunas that have a limited number of species, primarily secondary and amphidromous, which could be susceptible to the presence of introduced species. Xiphophorus fish demonstrate the ability to thrive in highly degraded environments, promoting their dispersion and amplifying the impact on the habitat and local fish, particularly small endemic fish, such as the Rivulidae and Poeciliidae.