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In the aquaculture industry, biocides are routinely used to treat parasitosis in fish, and researchers are continually developing sustainable alternatives that can replace these harsh chemicals. In this context, the objective of this study was to evaluate the effectiveness of a new natural compound, BiokosTM, for the treatment against Epistylis sp. in Carassius auratus fish. The infestation was identified by the presence of whitish plaques on the integument of five animals, and the diagnosis was confirmed through skin scrapings. BiokosTM is a lipopeptide derived from the bacteria Pseudomonas that can destroy the functionality of the cell membrane of ciliated protozoa. The action of BiokosTM does not harm animals and the environment because the compound degrades into amino acids and fatty acids within days. A 0.15 m3 (150 L) aquarium was treated with an Ich-AwayTM water conditioner manufactured by the Danish company Sundew ApS, which has BiokosTM as the active ingredient. Six tablets were added to the water daily for two days, and new skin scrapings were performed. The fish were clinically well and no longer possessed lesions or parasites. The results obtained indicate that BiokosTM can be an innovative and more sustainable alternative for controlling epistyliasis in ornamental fish.

This study aimed to search parasites in 333 ornamental fish from five Brazilian states (Ceará, Minas Gerais, São Paulo, Paraná and Santa Catarina). Fish were sent from eight farms located in the municipalities of Fortaleza, Patrocínio do Muriaé, São Francisco do Glória, Cascavel, Timbó, Iguape, Jacareí and Mairinque. All fish received anesthesia earlier to euthanasia procedures. After the search for parasites, it was verified that 70.6% (235/333) of fishes were infected by at least one type of parasite, being 12 types of parasites identified: monogeneans, digenean metacercariae, cestodes, nematodes, Lernaea cyprinacea, trichodinids, Piscinoodinium pillulare, Ichthyophthirius multifiliis, diplomonad flagellates, Ichthyobodo sp., Chilodonella sp., and Tetrahymena sp. The proportion of infected fishes among the farms is compared through statistical tests, besides, animal handling adopted in each farm is also discussed. The importance of ensuring fish health in order to make the ornamental freshwater fish industry economically viable and reduce losses in production is highlighted.

Cyprinid herpesvirus 3 has a worldwide distribution and presents high mortality rates in species of Cyprinus carpio, causing serious economic loss to the global aquaculture industry. The description of this infection in other ornamental fish species is still limited. For this purpose, 100 ornamental fish from 24 different species were tested by PCR for Cyprinid hespesvirus 3 and the positive samples represented 6% of the tested samples. Phylogenetic reconstruction, based on the Thymidine Kinase gene, revealed the existence of two distinct clades. One clade grouped a Brazilian sample with European and Asian genotypes of CyHV-3 and a second clade, containing only Brazilian sequences described in this study. All of the Brazilian sequences showed identity values greater than 97.7% when compared to each other. This is the first report of the occurrence of Cyprinid herpesvirus 3 in ornamental fish species in Brazil. These results in association with further studies of viral isolation and characterization can help in establishing effective surveillance and disease control program., (© 2022. The Author(s) under exclusive licence to Sociedade Brasileira de Microbiologia.)

Nontuberculous mycobacteria infection is one of the most common chronic bacterial diseases in ornamental aquarium fish and appears to be directly related to stressful husbandry practices. Furthermore, it also represents zoonotic potential. Here we present the isolation and characterization of non-tuberculous mycobacteria from diseased freshwater angelfish (Pterophyllum scalare) in São Paulo, Brazil. Nine discarded breeding females with signs of disease were evaluated. The fish exhibited lethargy, loss of appetite, cachexia, skin ulcers, and exophthalmia. At necropsy, four fishes presented macroscopic granulomas in the spleen. Mycobacterium chelonae, M. fortuitum, M. gordonae, M. intracellulare and M. peregrinum were isolated and identified by hsp65 PCR restriction analysis. Histopathological analysis revealed microscopic lesions compatible with mycobacteriosis, and Mycobacterium bacillus were observed by Ziehl-Neelsen stain. Notably, all Mycobacterium species identified in this study have already been reported in human patients; therefore, diseased animals may be a source of infection for people who handle fish and aquariums.

The genus Dermocystidium infects a wide range of animals. The host infection often occurs through the ingestion of endospores. The diagnosis depends on wet mounts and histopathological analysis of the affected tissue. The aim of this study was to investigate the incidence of Dermocystidium sp. infection on the skin of farmed striped catfish (Pangasianodon hypophthalmus) from a fish farm located in Fortaleza, Ceará state, northeastern Brazil. From these observations, we determined that 100% of the analyzed animals were infected with Dermocystidium sp. The wet mount and histopathology of the fish lesions revealed spore-filled cysts between the dermis and epidermis, encapsulated by connective tissue. Owing to a lack of research on the parasite and its prevalence among different fish species in Brazil and the rest of the world, additional studies are required to understand their endemicity in fish farms of Brazil, and consequently develop better disease prevention methods and increase the overall productivity.

Bacterial diseases are common in ornamental fish, more frequently associated with ubiquitous bacteria from the aquarium environment. The disease can lead to fish mortality and cause high economic losses if not rapidly controlled. The aim of this study was to identify the main causative bacterial agents of infection in ornamental fish with different clinical signs. A total of 126 freshwater fish, from 12 families and 38 species, with clinical signs were collected in a wholesaler in São Paulo, SP, Brazil. Samples were taken from the eye, skin ulcers, kidneys, and gills, plated on MacConkey, CHROMagar Orientation, and blood agar and incubated under aerobic and anaerobic conditions. Bacterial identification was performed by MALDI-TOF mass spectrometry. From the 126 studied animals, 112 were positive for bacterial isolation. Among the positive animals, 32.1% presented infection caused by a single bacterial species, while in the remaining 67.9%, two to six different bacterial species were identified. A total of 259 bacterial strains were obtained and classified among 46 bacterial species. The species of higher frequency were Aeromonas veronii (26.3%), Aeromonas hydrophilla (16.2%), Shewanella putrefaciens (7.3%), Citrobacter freundii (8.1%), Vibrio albensis (5.8%), and Klebsiella pneumoniae (4.2%). MALDI-TOF MS showed to be a rapid method for diagnosis of bacterial disease outbreaks in ornamental fish establishments.

This study identified the parasitic species in juvenile freshwater finfishes during the fattening stage, from a fish farm located in the Zona da Mata (MG), southeastern Brazil, and revealed both macro and microscopical lesions in fish gills. A total of 172 juvenile fishes of different species (Oreochromis niloticus, Ictalurus punctatus, Ctenopharyngodon idella, Cyprinus carpio, Astyanax bimaculatus and Brycon amazonicus) were transported to a laboratory in São Paulo city. The fish were sedated and then euthanized for parasitological analysis. All fish were infected by at least one parasite species. Ten different species of parasites were identified: Apiosoma sp., Epistylis sp., Ichthyobodo sp., trichodinids, Piscinoodinium pillulare, Ichthyophthirius multifiliis, Tetrahymena sp., monogeneans, Centrocestus formosanus metacercariae, and Dermocystidium sp. The best management practices and lack of sanitary control were also discussed.

The aim of this study is to report the occurrence of Lymphocystivirus in Brazilian ornamental fish. From 25 ornamental fish species submitted for molecular diagnosis, only one sample (Pomacanthus imperator) was positive, and its viral nucleotide sequence obtained clustered with sequences of genotype VII. To our knowledge, this is the first report on the genetic characterization of Lymphocystivirus in Brazil.

Scuticociliatosis, caused by an opportunistic ciliate protozoan, is responsible for significant economic losses in marine ornamental fish. This study reports the occurrence of Uronema spp., parasitizing ten species of marine reef fish at an ornamental fish wholesaler: Blue green damselfish (Chromis viridis), Vanderbilt's Chromis (Chromis vanderbilti), Pennant coralfish (Heniochus acuminatus), Threespot angelfish (Apolemichthys trimaculatus), Goldspotted angelfish (Apolemichthys xanthopunctatus), Sea goldie (Pseudanthias squamipinnis), Orchid dottyback (Pseudochromis fridmani), Threadfin butterflyfish (Chaetodon auriga), Vagabond butterflyfish (Chaetodon vagabundus), and Bluecheek butterflyfish (Chaetodon semilarvatus). Diseased fish showed disorders such as hemorrhages and ulcerative lesions on the body surface. Histopathological analysis of the muscle, liver, gut, kidney, spleen, gills, and stomach revealed hemorrhages and degeneration of muscle fiber, vacuolar degeneration of hepatocyte, inflammatory process and granuloma in the liver, atrophy of intestinal villi, inflammatory process and granuloma in the kidney, melanomacrophage centers, as well as inflammatory process in the spleen, epithelial cells hyperplasia and granuloma formation in the gills, and vacuolar degeneration and eosinophils in the stomach. Due to the severity of the disease, it is necessary to implement biosecurity measures with rapid and accurate diagnosis to minimize the risk of economic losses caused by Uronema spp.

More than 1.450 marine fish species are commercialized as ornamental fish and approximately 90% of these are wild-caught. Rainford's butterflyfish, Chaetodon rainfordi (McCulloch, 1923), is endemic to the western Pacific. This fish species belongs to one of the main ornamental fish families imported into Brazil. Haliotrema is a genus of the family Dactylogyridae. Species of this genus have very interesting host associations and geographic distributions. The aim of this study was to report on occurrences of exotic Haliotrema aurigae in diseased Rainford butterflyfish that were imported to Brazil. One Rainford's butterflyfish with suspected parasitic disease was euthanized and subjected to skin and gill scraping. The parasite specimens were mounted on semi-permanent slides with Hoyer's solution for morphological analysis of sclerotized structures. The hard-sclerotized structures of these specimens were compared and were identified as those of Haliotrema aurigae (Yamaguti, 1968). These results emphasize the importance of implementation of correct control measures at the country's borders, to avoid the introduction of exotic parasites. In addition, it can be emphasized that the easy adaptation of this parasite to new environments is a concern for ornamental fish farmers.

Cryptocaryon irritans is an obligate parasitic ciliate protozoan of wild and cultured marine fish. It causes white spot disease, and infections with this pathogen can cause significant losses for aquarists and commercial marine cultures worldwide. This study reports the occurrence of C. irritans parasitizing the ornamental reef fish, yellowtail tang, Zebrasoma xanthurum. Six days after being introduced to a new environment, 11 yellowtail tangs had white spots scattered across their bodies and fins. Suspicion of infection with C. irritans was evaluated by scraping the skin to confirm clinical diagnosis. After confirmation, the yellowtail tangs were transferred to a hospital aquarium and treated with the therapeutic agent Seachem Cupramine® for 15 days. During the treatment period, the copper concentration was monitored daily. At the end of the treatment, none of the yellowtail tangs showed clinical signs of white spots on their bodies, and skin scraping confirmed the yellowtail tangs were no longer infected. Subsequently, the yellowtail tangs were released for sale.

The capsalid monogenean Neobenedenia melleni is known as a lethal pathogen for captured marine teleost ornamental fish, if left untreated. This study reports the occurrence of N. melleni parasitizing four species of ornamental reef fish imported into Brazil and maintained in quarantine: Arabian angelfish (Pomacanthus asfur ), yellowbar angelfish (Pomacanthus maculosus), regal angelfish (Pygoplites diacanthus), and bluecheek butterflyfish (Chaetodon semilarvatus). Ten days after the beginning of quarantine, some fish showed behavioral alterations, such as irritability, and corneal opacity, which were rapidly diagnosed to be caused by monogenean parasites by body surface scraping. The fish from the same batch were treated with two applications of 2 mg L-1 praziquantel each at an interval of four days. Seven days after the first treatment, the mucus surface of the fish was re-examined, which did not reveal the parasites presence being delivered for commercialization.

Megalocytiviruses have a worldwide distribution, causing serious economic loss to the global aquaculture industry. They also present a threat to ornamental fish trade because megalocytiviral infections have unspecified symptoms, making early diagnosis difficult. In this study, 100 ornamental fish from 24 different species were tested by PCR for megalocytivirus, with a 47% positive rate being identified. Phylogenetic reconstruction, based on the major capsid protein (MCP) gene, clustered all Brazilian samples into a single clade, showing identity values ranging from 99% to 100% when compared to each other. This is the first report of megalocytivirus infection in some ornamental fish species in Brazil.

Scuticociliatosis, which is caused by an opportunistic ciliate protozoan, is responsible for significant economic losses in marine ornamental fish. This study reports the occurrence of Uronema sp., which was found to be parasitizing three species of marine reef fish imported into Brazil and maintained in quarantine: Vanderbilt's Chromis (Chromis vanderbilti), blue-green damselfish (Chromis viridis), and sea goldie (Pseudanthias squamipinnis). During the quarantine period, some fish presented with behavioral disorders and hemorrhages and ulcerative lesions on the body surface. Histopathological analysis showed hemorrhages, inflammation comprising mononuclear and granular cells in the skeletal muscle, and necrosis of the skin and the secondary lamellae of the gills, and parasites were also observed in the renal capsule. The absence of transboundary measures available to prevent the occurrence of ornamental fish diseases is also discussed.