This study analyzed the ectoparasitic fauna of freshwater ornamental fish marketed by a wholesaler in the São Paulo city. This study was undertaken from January to December 2016. A total of 268 freshwater ornamental fishes of various species that showed signs of disease after arrival at the establishment were evaluated. From the individuals, ectoparasites were collected by scraping off the skin and gills and visualized using an optical microscope at increasing magnification of 40x, 100x, 200x, and 400x. Parasites were found in 220 animals (82%); 11 different parasites were recorded, which included Ichthyophthirius multifiliis, Monogenes, Metacercariae (Centrocestrus formousus), Epistylis spp., Chilodonella spp., Lernaea spp., Tetrahymena spp., Piscinoodinium spp., Trichodina spp., Ichthyobodo spp. and Argulus spp. The occurrence of the parasites in the establishment studied can indicates that the suppliers’ lack of good sanitary and hygiene practices in the management of their facilities, consequently distributing infested animals and putting the whole supply chain at risk.

Aquarium ornamental pet fish constitute a major segment in the pet industry, with the United States, Europe, and Japan dominating the market. There are approximately 1,500 marine fish species and over 4,500 freshwater fish species commercialized as aquarium ornamental pet fish. Fish are the fourth most common pet present in Brazilian homes. In Brazil, aquarium ornamental pet fish can be marketed and distributed from different parts of the Brazilian territory and the world. Commercialization and circulation of living animals without the use of adequate prophylactic management procedures enables dissemination of a number of agents responsible for infectious diseases. Aquarium pet fish can also carry pathogenic agents, of bacterial, viral, fungal, or parasitic etiology, that may have a zoonotic feature endangering the persons handling the animals. This review presents the main pathogenic infectious agents of bacterial, viral, andfungal etiology that affect aquarium pet fish, as well as the prevention and control measures to ensure sanitary excellence in this segment.