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The multi-billion dollar trade in ornamental fishes has rarely been reliably monitored. Almost all coral reef fishes are wild-caught, and few scientific analyses have attempted to elicit exact quantities and identify species involved. The consequences of the removal of millions of these fishes are poorly understood. This article collates and examines available information, including scientific studies and formal publications, in order to create a more accurate picture of this commerce. We demonstrate that it is almost impossible to analyse the trade in marine ornamental fishes due to a lack of data, and that available data for marine species is frequently combined with that for freshwater species. Figures range from 15 to 30 million coral reef fishes being traded annually, but could be as high as 150 million specimens. The global value of this trade was only estimated for 1976 and 1999 between USD 28–40 million. This review highlights the urgent need to introduce a specific harmonised system tariff code and for a global monitoring system, such as the Trade Control and Expert System already in use in Europe, in order to gather accurate and timely information on the number and species of marine ornamental fishes in commerce, where specimens originated, and whether they were wild-caught or captive-bred.

Fishes belonging to the family Pomacentridae (clownfishes and damselfishes) dominate the marine ornamental fish trade. However, only 1.0–4.2% of marine ornamental species traded in the US are reproduced in captivity, while the vast majority are wild-caught, an environmentally damaging practice. Reproduction in captivity undoubtedly is an adequate strategy for moving in the direction of sustainability. Among ornamental marine fish species, the most spectacular advances in captive breeding have been made for clownfishes. Twenty-five species of clownfishes have been captive-bred for commercial purposes. Furthermore, numerous clownfish varieties or color morphs have been developed through selective breeding and hybridization between species has been achieved. Of at least thirty-nine damselfish species that have been reproduced in captivity, only nine are currently commercially available. This is related to the small size of eggs and to the underdeveloped state of altricial damselfish larvae. In addition, long larval periods (up to 50 dph) and low survival rates (typically less than 10%) create barriers to the success in commercial aquaculture of damselfishes. Improvements in the low survival of damselfish larvae can be expected as zootechnical aspects for larviculture are perfected (especially improved nutrition).

In 2019, a melioidosis case in Maryland, USA, was shown to have been acquired from an ornamental fish tank contaminated with Burkholderia pseudomallei bacteria, likely derived from Southeast Asia. We investigated the presence of B. pseudomallei in ornamental fish tanks in the endemic area of Vientiane, Laos.

Aquaponics, a combination of fish farming and soilless plant farming, is growing in popularity and gaining attention as an important and potentially more sustainable method of food production. The aim of this study was to document and analyze the production methods, experiences, motivations, and demographics of aquaponics practitioners in the United States (US) and internationally. The survey was distributed online using a chain sampling method that relied on referrals from initial respondents, with 809 respondents meeting the inclusion criteria. The majority of respondents were from the US (80%), male (78%), and had at least a high school degree (91%). The mean age of respondents was 47±13 years old. Most respondents (52%) had three years or less of aquaponics experience. Respondents typically raised tilapia or ornamental fish and a variety of leafy green vegetables, herbs, and fruiting crops. Respondents were most often motivated to become involved in aquaponics to grow their own food, for environmental sustainability reasons, and for personal health reasons. Many respondents employed more than one method to raise crops, and used alternative or environmentally sustainable sources of energy, water, and fish feed. In general, our findings suggest that aquaponics is a dynamic and rapidly growing field with participants who are actively experimenting with and adopting new technologies. Additional research and outreach is needed to evaluate and communicate best practices within the field. This survey is the first large-scale effort to track aquaponics in the US and provides information that can better inform policy, research, and education efforts regarding aquaponics as it matures and possibly evolves into a mainstream form of agriculture.

The ornamental fish trade involves multiple phases, from acquisition—whether through wild capture or aquaculture—to the final destination, often including long transport routes. Throughout this trade, fish encounter several stressors like handling, improper maintenance methods, high or inadequate stocking densities, poor water quality, and mechanical disturbances during transport. The varying levels of care provided by aquarists also influence the long-term welfare of these animals, with many fish being treated more as ornaments rather than sentient beings. Worsening these issues, there is a lack of scientifically grounded guidance for hobbyists and caregivers, important gaps in legislation concerning fish welfare, and limited oversight in the ornamental trade. Nevertheless, some international organizations and grassroots projects have been working to promote responsible practices and disseminate educational resources. However, the need for efficient welfare standards, legislation, and comprehensive information for all stakeholders involved in this sector remains critical. Here, we synthesize the problems in the ornamental fish trade and suggest some solutions to reduce the impacts of management practices on the welfare of these fish.

BackgroundThe invasion success of introduced freshwater fishes is influenced by many factors, including ecological, species, and socioeconomic characteristics. Most studies that document the importance of these characteristics are conducted at local scales and/or focus on a single step of the invasion process. In this study, we aim to determine the species characteristics, ecological characteristics, and socioeconomic characteristics of non-native freshwater fish invasions. Our assessment was done at the global scale and considers all three steps of the invasion (i.e., introduction, establishment, and impact). For this purpose, we applied generalized linear models to 20 variables collected for 307 non-native species and modeled them as a function of ecological characteristics (i.e., environmental features), species traits (i.e., functional and morphological), and socioeconomic characteristics (i.e., human use and introduction pathways). We considered the number of countries in which each species was introduced, established, or had ecological impacts as a proxy of invasion step success. We also explored the specifics of species introduced through the aquaculture and the ornamental fish trade pathways.ResultsWe found that non-native freshwater fishes with broad diets, high parental care, and multiple introduction pathways are the most widely introduced and established worldwide. The number of countries with impacts reported was best explained by the type of introduction pathway (i.e., aquaculture or fisheries). Moreover, among non-native species introduced through aquaculture, those belonging to Cypriniformes and having broad diets were the most widely introduced and established species. In contrast, the species introduced through the ornamental fish trade pathway belonged to various taxonomic orders but were mainly native to tropical regions.ConclusionsConsidering several types of factors is important when analyzing the invasion success of freshwater fish and disentangling the different invasion steps. These findings have strong implications for anticipating the profile of species with a high potential to invade many countries.

To understand how Neotropical freshwater fishes (NFF) benefit society, we conducted a broad literature survey to (i) map and list the ecosystem services (ES) generated by these organisms, and (ii) investigate how human activities have affected the ecosystem service chain. We found sound evidence that NFF contribute directly and indirectly to the generation of several provisioning, regulating, supporting, and cultural services. Provisioning services have been widely recognized, especially those related to fisheries, but this class also included ornamental fish, genetic pools, medicines, aquaculture, and bioindicators. Other services remain less understood and largely ignored by society. Regulating services included seed dispersal, decomposition, and top-down control, while supporting services included nutrient cycling, habitat quality, and ecosystem engineering. Cultural services associated with NFF included recreational fishing, tourism, fishkeeping, education, production of scientific knowledge, in addition to values linked to traditional communities, such as local knowledge, cosmology, and existential foundations. Human activities have negatively impacted the generation of ES, especially those related to fishing and food provisioning. This review indicates that Neotropical fishes benefit society in multiple ways, but it is imperative to improve our understanding about those benefits, and to increase conservation efforts directed to this important component of global biodiversity.

The effect of green tea ( Camellia sinensis ) iron oxide nanoparticles (nano-Fe) on the effectiveness, growth, antioxidant capacity, and immunological response of Trichogaster trichopterus (Blue gourami) fingerlings was investigated. UV–Visible, Fourier Transform Infrared, Scanning Electron Microscopy, Energy Dispersive X-ray, X-ray diffraction, Dynamic Light Scattering, and Zeta Potential spectroscopy were used to evaluate the biologically synthesized nano-Fe. Characterization revealed the hexagonal and spherical morphology with an average diameter of 114 nm. Six different experimental diets were supplied to the fish in duplicate for 60 days. The first diet served as a control (no nano-Fe supplementation), whereas the remaining five diets contained nano-Fe at concentrations of 10, 20, 30, 40, and 50 mg/kg (D1 to D5). The results indicated that fish fed a nano-Fe diet at a concentration of 40 mg/kg had improved growth performance, biochemical constituents, hematological parameters, and antioxidant activity in T. trichopterus , implying that it might be used as a vital feed supplement in ornamental fish culture.

Attractive colouration of ornamental fishes is an important quality criterion in the aquarium fish industry. Ornamental fish cannot synthesize colour-producing carotenoid pigments and therefore must rely on dietary carotenoids in natural or synthetic forms to achieve their colour pigmentations. The aim of this review is to compile and summarize recent investigations into different carotenoid sources used in ornamental fish feed formulations and to highlight the research gaps and investigation needs in the field of aquaculture. The natural carotenoid sources which have been widely used for enhancing colouration are non-photosynthetic organs of higher plants, microalgae, seaweeds, crustacean by-products, and red yeast. Consumers mostly prefer to use natural sources rather than synthetic sources. The problem faced by aquaculturists is stabilization of the gained skin colour after terminating feeding of the fish. Advanced investigations are needed to identify the stability of the colouration in the ornamental fish during their life cycle. Further, this review encourages the use of other available natural carotenoid sources in the ornamental fish industry in order to reduce the use of synthetic pigment products and invites research to be done on a genetic level in order to fully understand colour distribution patterns and sustainability of colouration gain.

The Amazon basin is the world’s largest hydrographic basin, in terms of both its total area and its species diversity, with more than 2,700 species of fish. Despite this diversity, the data available on the fish fauna of the Amazon basin are still relatively scant and incomplete, in particular from the streams and floodplain lakes of the lower Amazon, which may contain a large proportion of the still undescribed species of the basin. Many of these species are expected to be of interest to the ornamental fish market. The investigation of the diversity of potential ornamental fish using molecular tools is even more limited. Given this scenario, the present study employed DNA barcoding to investigate the diversity of ornamental fish found in two streams and a floodplain lake of the lower Amazon. The mitochondrially encoded cytochrome c oxidase I (MT-CO1) molecular marker was used to identify the taxa, in combination with morphological keys. A total of 51 ornamental species were identified, representing 13 families and three orders. A majority of the species were found at only one of the sampling points, which indicates that the distribution of the species is influenced by ecological factors. The most speciose order was the Characiformes, followed by the Cichliformes and Siluriformes, while the family with the greatest diversity of species was the Acestrorhamphidae (31.3% of the total number of species), followed by the Cichlidae (27.4%), and the Lebiasinidae (9.8%). One specie was registered in the region of the lower Amazon for the first time, and evidence was found of the possible existence of species not formally described of Aphyocharax , Astyanax , Apareiodon and Hemigrammus .