Fish Welfare in the Ornamental Trade: Stress Factors, Legislation, and Emerging Initiatives

Abstract

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.

1. Introduction

One important concern of the Anthropocene is the effect of human activities on animal welfare, as many animals are reared in artificial environments for different purposes, ranging from scientific research to livestock. The growth of global aquaculture, for example, has driven the debate about fish welfare, which, nowadays, is viewed with the same importance as that of mammals [1]. More attention paid to fish’s quality of life has emerged, particularly in this century, with scientific evidence increasingly supporting the idea that fish are sentient and capable of experiencing pain, although some skepticism remains. While certain studies question fish pain and sentience due to conflicting findings or other human-related reasons [2], a substantial body of research shows that fish possess nociceptors and nerve fibers that receive and conduct painful information to their brain [3,4,5,6], where it is then processed [4,5,6,7]. In response to pain, fish exhibit complex behavioral changes, such as the suspension of normal behavior, reduced activity, and abnormal behaviors [8,9], which are not mere reflexes [3,5,6,10]. These responses can be alleviated with analgesics [6,10]. Zebrafish (Danio rerio) are motivated to stay in environments containing analgesics, even when unfavorable [11], a species now widely used in translational pain research to study pain behaviors, mood-related disorders, and analgesic treatments [12]. Additionally, fish show signs of other negative affective states, such as anxiety and fear [5,13,14]. Fish also show complex social interactions and use memory to make decisions [15], besides other even more complex cognitive abilities [9]. Recently, studies have shown that fish are capable of self-recognition [16] and mental evaluations of their own size when fighting each other [17], suggesting some degree of consciousness. Thus, we can no longer deny that fish are sentient and warrant welfare considerations akin to other vertebrate animals.

Fish show adaptations, such as specific behaviors, needs, and coping styles, which permit them to survive in natural environments [18]. However, artificial environments are markedly different from their natural habitats and can negatively affect fish welfare [19]. For instance, in aquaculture, it is common to find space constraints, unusual aggregations, barren environments, handling, transportation, and other artificial stressors that fish are not naturally equipped to cope with [20]. Although efforts to minimize stress have been made in the aquaculture industry, there is still much to be improved, not only in aquaculture, but especially in scenarios in which this issue is just starting to be considered, such as the ornamental fish trade. The ornamental fish trade is a rapidly growing global industry, involving more than thousands of species and generating a billion dollars annually. Despite its scope, research into the welfare of ornamental fish remains limited when compared to farmed fish, and welfare guidelines are often based on a small number of aquaculture species, as pointed out below. The high species diversity in this sector poses significant challenges for standardizing husbandry practices, and fish are frequently subjected to stressors throughout the production chain—including poor water quality, inappropriate social environments, and especially high mortality rates during transport. These issues underscore the urgent need to better understand and regulate ornamental trade to improve animal welfare. In this review, we highlight the most pressing welfare concerns and challenges in the ornamental fish trade and discuss potential strategies to mitigate the negative impacts of current management practices. We begin by examining the welfare challenges faced during the different phases of trade and at ornamental fish fairs (Section 2.1 and Section 2.2), then expand the discussion to include the evaluation of welfare indicators (Section 3), the scarcity of scientific data (Section 4), the lack of specific legislation (Section 5), current initiatives to improve welfare (Section 6), and finally, a reflection on the terminology used to describe these animals, proposing a shift from “ornamental” to “pet” fish (Section 7).

2. Fish Welfare in the Ornamental Trade

When discussing fish welfare in ornamental trade, it is essential to distinguish between the different phases of the commercial chain and the general stressors that affect fish welfare throughout these stages. This section begins with an overview of the current situation and knowledge gaps and the increasing need for research on the welfare of ornamental species. We then describe the main welfare challenges associated with the specific phases of the trade process—including capture or farming, transportation, retail, and final ownership—highlighting how each step can negatively affect fish welfare (Section 2.1). Subsequently, we address broader, ongoing stressors, such as water quality, stocking density, environmental structure, and public perceptions of fish suffering, which often persist beyond transport and temporary maintenance into the animals’ final environment (Section 2.1). To conclude this section, we address the problematic view of ornamental fish as ‘disposable’ objects. Finally, we present the challenges related to ornamental fish fairs, illustrating how inadequate conditions at these events can severely compromise the welfare of these aquatic animals (Section 2.2).

Besides being farmed for human consumption, fish are caught in the wild to be sold as food, used as experimental models in laboratories, exposed in public aquaria, caught at pay-to-fish or catch-and-release establishments, and, finally, also kept in ornamental aquaria in homes. However, until recently, fish welfare research focused primarily on food fish in aquaculture systems [21,22,23,24]. However, addressing this subject in ornamental trade is also critical, as there are nearly 6000 fish species used worldwide in ornamental aquaria [25,26,27], including about 4500 freshwater and 1450 marine species [25,26,27,28]. Even though ornamental species have been receiving some attention recently [26,29,30], few studies have considered how to improve their welfare [31]. Making a rough comparison, while we found 85 and 30 papers when looking for studies addressing the welfare of ornamental fishes by using the terms ‘ornamental fish’ or ‘aquarium trade’ and ‘welfare’ as topics, 1322 and 1946 papers were found when looking for ‘farmed fish’ or ‘aquaculture’ and ‘welfare’ terms as topics in the ©Web of Science international database, respectively. When we combined the terms ‘ornamental fish’ or ‘aquarium trade’ and ‘wellbeing’ or ‘well-being’, we found 9, 11, 0, and 5 papers, respectively, whereas 59, 155, 141, and 362 papers were found when combining ‘farmed fish’ or ‘aquaculture’ with ‘wellbeing’ or ‘well-being’ terms. This underscores the pressing need for more research into the welfare of ornamental fish, especially since this sector involves a substantially higher number of species compared to those farmed for human consumption in aquaculture. A consequence of understudied ornamental species is that legislation, guides, and protocols may be based on fish species reared for food, such as salmon (Salmo salar) and Nile tilapia (Oreochromis niloticus). In this scenario, it is critical to increase our understanding of greater varieties of species to better make decisions on fish husbandry.

Ornamental fishes are among the most popular companion animals globally [25,32], with an estimated global trade value ranging from USD 15 to USD 30 billion a year [26,33,34]. More than 125 countries participate in the ornamental fish trade, underscoring its global scope [35]. Since the 1970s, this trade has been growing at an annual rate of 14% [36,37]. However, this production chain exposes fishes to a variety of stressors and environments, which may negatively affect their welfare, including fish transport, one of the main stressful conditions [30]. Therefore, several studies have considered welfare issues and improvements during transport (for review, see [22,30,38,39]), although research about welfare refinements post-transport to improve recovery is still lacking [31]. For instance, the social composition of the tank with conspecifics or heterospecifics has an important effect on the behavior of ornamental fishes after transportation, thus representing a way in which retailers may improve fish welfare [31]. Taking into account that ornamental fish [40,41] and other aquatic animals [42] are now also traded online, welfare concerns related to their transportation have become even more significant, in addition to the already problematic issue of increased invasion potential. In Brazil, social media such as Facebook have been observed to be used by fish sellers to market over 600 marine and freshwater species of ornamental fish [41], including open announcements of prohibited species in mostly non-native Facebook groups, which then raises issues related to selling illegal species. Furthermore, ornamental fishes are frequently exposed to poor water quality, inappropriate stocking densities, diseases, and injury [22], with issues that are very comparable to those experienced by food fish in aquaculture [22,43]. However, fish welfare in the ornamental trade is impaired at several other steps from their origin to reaching retailers’ and caregivers’ hands.

2.1. Fish Welfare Issues in the Ornamental Trade Phases

The ornamental fish trade has several phases and usually involves a long journey between obtaining the animals and reaching the final destination (Figure 1), which may be local or even international. Thus, the phases of this trade are linked by long transport routes (by road, air, and/or sea). The first step is to obtain the fish, which can be caught in the wild or farmed in aquaculture [44]. Once obtained, these fish are kept in a holding facility until they reach the exporter, who sends the fish to the area/country of destination. When international transportation is necessary, the animals are previously quarantined and then inspected at the border upon arrival in the destination country [45]. In the next step, fish enter the care of the importer, who may pass the animals directly to retailers or use a wholesaler as an intermediary, adding another phase in the process. From there, retailers keep the animals until they are sold to their final destination, which is usually hobbyists, people who have aquaria with fish at home, or aquaria/pond exhibitions, such as in stores and shopping malls.

Fish are subjected to multiple stress-inducing factors throughout the ornamental trade chain, from capture and transport to retailers to final sale and destination (Figure 1). One of the most immediate welfare challenges in this chain is handling (Figure 1), which often involves netting, removal from water, and physical contact without protective gloves. These procedures can compromise the fish’s protective mucus layer and scales, increasing its susceptibility to disease [22]. Another major concern is the impact of stocking density (Figure 1), both during transportation and in holding systems, which can vary across species, with incorrect densities being detrimental in different ways [46]. Overcrowding can lead to increased cortisol levels [47], aggressive interactions, and low water quality [30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45], including oxygen depletion and the accumulation of toxic metabolite wastes [48], while densities that are too low may negatively affect species that rely on shoaling behavior for social stability [20]. Inadequate water quality (Figure 1), often a consequence of an excessive stocking density and insufficient mechanical, chemical, and biological filtration, is also a key factor in causing stress and deteriorating fish welfare [22,30,48], leading to behavioral changes [49], in addition to fish mortality [45]. Social compatibility also plays a role (Figure 1), as the presence of incompatible species can increase aggression or trigger predatory behavior. Additionally, mechanical disturbances during transportation (Figure 1)—usually caused by water movement in plastic bags—can further compromise health and increase vulnerability to infections [50]. Some studies have shown that the use of anesthetics, such as clove oil, can mitigate the stress caused by transportation without changing behavior in Nile tilapia [51]. Clove oil also mitigates the effect of transportation on stress in the ornamental Siamese fighting fish (Betta splendens) [52], for instance, thus showing that some anesthetics are good candidates for effectively reducing stress in fish kept under harmful conditions. However, clove oil interferes with oxidative stress in sea bream (Sparus aurata) [53], thus indicating that there is still much research to be conducted to find solutions during this important phase of the ornamental trade.

While these are some of the primary challenges identified, other factors such as inadequate feeding practices or poor environmental structures also contribute (Figure 1). Problems with feeding management include, for example, pre-transport food deprivation or even overfeeding in production systems, which can affect water quality and lead to behavioral and performance problems, in addition to disease risk for these animals [22,30]. Moreover, feed pellets that are not appropriately sized for the specific life stage of the fish, as well as an inadequate feeding frequency, can negatively impact the welfare of ornamental fish. With regard to environmental structure, captive environments are typically more monotonous and often fail to meet the specific needs of each species. This is no different for ornamental fish. Therefore, important issues regarding their welfare are the maintenance conditions and environmental structure at their final destination, which may vary greatly. There are aquarists whose hobby is to care for these fishes, frequently simulating environmental conditions and offering characteristics similar to the species’ natural habitat. On the other hand, the public can also use fish as ornaments, that is, not taking into account their welfare conditions. This poses a significant issue regarding fish welfare in the ornamental trade, meaning that, besides suffering during each of the trade phases before reaching their final destination, fish also suffer in the poor conditions of ornamental aquaria, probably for their whole life.

This is emphasized by the fact that people commonly struggle to accept the concept that fish experience suffering (Figure 2), probably because these aquatic animals live in an environment completely different from ours (i.e., water bodies) and do not have many facial or body expressions similar to ours [54]. Additionally, many freshwater species used as ornamental fishes are sold at a very low price, which further devalues their lives. Figure 2 summarizes the main fish welfare challenges encountered in the chain discussed here, including these. In ornamental fish stores, it is not difficult to find people mentioning that if their new fish dies, they can always buy another. Based on personal experiences, sometimes, the seller even tries to warn such people that the fish being purchased will not live well in the water or social conditions of these people’s aquaria, but the low price of these animals usually makes people take them home anyway. In a case study conducted in Indonesia, the quality and affordable price of fish were the factors that most influenced purchasing decisions regarding ornamental freshwater fish [55]. Overall, compared to the food supply chain, for example, individual deaths in the ornamental trade generally cause very small losses for producers, retailers, sellers, and consumers. Thus, many ornamental fishes end up being treated as ‘disposable’ objects (Figure 2).

2.2. Ornamental Fish Fairs

In addition to aquarium stores and pet shops, there are ornamental fish fairs in some countries around the world, like Brazil and Indonesia, where these aquatic animals are sold, both for resale and to individuals who wish to set up their aquaria at home. From personal observations and analysis of video footage available on YouTube, it is clear that some of these fairs are held in unstructured sheds, thus lacking the basic resources to ensure the minimum welfare conditions for the fish. For instance, the absence of aquaria or tanks with the necessary equipment to maintain water quality and temperature during such fairs is common. Consequently, fish are exhibited in plastic bags suspended or arranged on the ground, frequently at high stocking densities, with no control over temperature and light. All these conditions impair the welfare of these aquatic animals, resulting in distress and even mortality. Such practices are unacceptable and, in many cases, contradict the principles of responsible aquarium management. It is, therefore, incumbent upon consumers and aquarium hobbyists to adopt a more critical and informed approach—by choosing sellers who demonstrate transparency, provide proper care information, and follow recognized fish welfare practices. Therefore, it is essential to support initiatives that promote good practices at ornamental fish fairs.

3. Fish Welfare Indicators

The lack of easily discernible facial expressions or vocalizations in fish usually makes it challenging to identify signs of stress, discomfort, or pain in such aquatic animals when compared to mammals. In addition, there is a vast diversity of fish species, each with a distinct morphology, as well as behavioral requirements. That said, several studies have identified/described specific physical, physiological, and behavioral indicators that may be useful in efforts to assess welfare in production settings (e.g., [56,57,58,59]). These indicators are referred to as operational welfare indicators (OWIs). However, there is currently no evidence that OWIs have been applied to ornamental fish [30].

Although protocols to assess OWIs in farmed fish are well-established, there are many challenges in establishing OWI identification in the ornamental chain, which can be broadly classified into three main categories. (1) Firstly, the animals in question are smaller than those typically farmed, which makes it difficult to assess their welfare by using common indicators applicable to larger animals. For instance, cortisol—the ‘stress hormone’—is commonly evaluated by its blood concentration using ELISA (Enzyme-Linked Immunosorbent Assay) methods, which have been validated for fish [60] and are relatively cheap, but require that fish have a certain size that allows for enough blood collection. Thus, this technique cannot be applied to several ornamental species, as most are too small, such as the Siamese fighting fish, guppies (Poecilia reticulata), and neon cardinal (Paracheidon axelrodi). Despite this, there are alternative techniques to measure cortisol, such as from the body, gills, and mucus, but some lack the same precision as the blood cortisol, whereas others are more expensive [61,62]. On the other hand, measuring water cortisol has become a useful technique for small fish, as it is not invasive [22]. Other stress indicators, like measuring glucose concentrations [63] or heart rate [64], are even more difficult to access in small fish, except for respiratory rate measured by opercular beat rate [30]. (2) Secondly, the ornamental fish trade involves a far greater number of species than traditional aquaculture production chains. While only hundreds of species are farmed globally for human consumption, thousands are traded as ornamental fish, making the establishment and control of operational welfare indicators (OWIs) considerably more challenging. (3) Thirdly, the practices of exporting/importing fish from the ornamental production chain make the issue even more complicated, as logistics prevent constant vigilance of fish conditions.

Although there are challenges, research has indicated that behavioral observation and other visual indicators (e.g., coloration changes, injuries, and swimming patterns) are facilitated in the ornamental trade due to the frequent use of glass tanks to keep fish. Jones et al. [30] suggested some non-invasive OWIs that can be practically employed to assess the welfare of ornamental fish. Such indicators were classified into the following two categories: behavioral and non-behavioral OWIs. While the behavioral OWIs encompass alterations in feeding/foraging, aggression patterns, and swimming behavior, the non-behavioral OWIs focus on morphological alterations (e.g., coloration changes and the presence of wounds), ventilation/respiration changes, and checking the occurrence of infections/disease [30]. Consequently, the assessment of fish welfare in the ornamental trade needs the integration of multiple indicators. While each species has its particularities and needs that must be taken into account, observing fish behavioral patterns and physical health can provide fundamental information to identify possible welfare problems and the necessary interventions. It is, therefore, important that professionals involved in the ornamental fish chain on the one hand and hobbyists and caregivers on the other use a comprehensive approach based on scientific evidence to monitor and ensure the health and welfare of fish in this chain.

4. Lack of Scientific Information

A variety of aquarium manuals are available, in both digital and printed formats, which provide information on a range of topics, from the fundamental principles for novice hobbyists to more advanced concepts. These manuals cover everything from how to set up your first aquarium to how to maintain and breed your fish. However, this information is frequently based on the experiences of individuals who have acquired the knowledge required to raise these animals independently, typically through a process of trial and error. These manuals usually lack scientific information, which poses a problem for fish welfare in this trade (Figure 2). In this sense, knowledge that has been tested and proven to encourage the best practices for breeding and keeping fish, particularly with regard to their welfare, is mostly neglected. For example, the weekly renewal of 50–90% of the water in an aquarium is a common recommendation in manuals to maintain a healthy environment for fish (e.g., Goldstein’s recommendation manual [65]). Gauy et al. [66], however, demonstrated that 50% water renewal in the aquarium of angelfish (Pterophyllum scalare) resulted in increased aggressiveness within the group for at least 24 h, resulting in high stress levels and physical injury in these fish. Moreover, these authors demonstrated that 25% renewal of the aquarium water is sufficient to maintain water quality, while having less impact on fish aggression, which returns to baseline levels within an hour of renewal [66]—a finding differing greatly from Goldstein’s recommendation manual.

Another example is the treatment of disease, such as the use of salt to control specific parasitic infestations in fish. While manuals typically stipulate disparate salt concentrations and treatment durations for fish (e.g., [67]—“25–40 teaspoons of salt per 20 L of water”, equivalent to 6–10 g/L), empirical evidence indicates that salt concentrations and treatment times vary depending on the species of fish and the degree of infection (or review, see [68]). For example, black mollies (Poecilia sphenops) infected with white spot responded well to a 10 g/L salt bath at 27 °C, with complete parasite clearance observed after 3 days and no mortality [69]. In contrast, iridescent shark catfish (Pangasianodon hypophthalmus) required 15 days of treatment at 1% salt combined with elevated temperatures (24–30 °C), though mortality was high [70], likely due to late-stage infection [69]. On the other hand, survival outcomes improved when the same treatment was administered to angelfish (Pterophyllum scalare) and gold gourami (Trichopodus trichopterus), presenting a lower parasite burden [70]. Furthermore, the authors highlight the lack of information on the effects of the prolonged exposure of fish to varying salinities, which may result in reduced fish welfare. For instance, Da Silva et al. [71] observed alterations in the structure of the blood and gills of Goldfish (Carassius auratus) maintained at a salinity of 5 g/L for a period of 21 days. A recent study showed that sodium chloride treatments significantly impacted stress hormones and gene expression in Siamese fighting fish, underscoring the need for scientifically informed dosing rather than generalized recommendations [72]. Therefore, it can be reasonably deduced that the information provided in manuals may not necessarily be designed to enhance the welfare of fish, but rather to ensure their survival. Nevertheless, certain actions may induce stress, injury, and disease in these animals, yet still maintain their survival. Given this scenario, we suggest some actions to be implemented to disseminate practical guidelines that are scientifically validated. For instance, it should be mandatory to cite scientific references for each recommendation in ornamental fish guidelines, although this would require legislation. An effort should be made to create an international guideline platform to disseminate adequate recommendations, as well as highlight the procedures that can harm fish health and welfare.

5. Lack of Legislation

The lack of legislation and supervision in the ornamental fish trade is another issue that requires attention (Figure 2). Considering the Brazilian legislation (IBAMA Ordinance No. 102/2022, https://www.in.gov.br/en/web/dou/-/portaria-n-102-de-20-de-setembro-de-2022-430816182) (accessed on 10 March 2025), for instance, the ordinance that establishes norms, criteria, and standards related to the import and export of ornamental fish, the welfare of these aquatic animals is neglected. Such ordinance basically covers the species that may or may not be transported, the registration of the producer or the license to catch the fish, and concerns surrounding the reintroduction of species that have been genetically modified or that may represent a risk of biological invasion. There is no mention related to fish welfare. Therefore, significant gaps remain in the promotion of welfare practices across all stages of the ornamental fish trade—including obtaining fish, their maintenance in holding facilities, transportation, care by retailers or wholesalers, and, ultimately, at their final destination in private homes or public aquaria (Figure 1). This pattern can also be seen in major exporting countries, where legislation often focuses on disease control and trade regulation to the exclusion of specific animal welfare criteria. The Singaporean government, https://www.customs.gov.sg/businesses/national-single-window/tradenet/competent-authorities-requirements/avs-fish/ (accessed on 5 May 2025), for example, enforces sanitary and licensing measures for ornamental fish exporters. However, there are few public guidelines on the minimum standards for the housing, transport, and handling of fish. This limited approach contrasts strongly with some countries that have made progress in regulating and disseminating information about good practices in the ethical management of these animals. To the best of our knowledge, the United Kingdom and the United States are among the few countries with more advanced regulations that explicitly address fish welfare and incorporate ethical management practices for these animals. In contrast, when reviewing legislation from other countries, we found little to no specific or relevant provisions regarding the welfare of fish.

The UK, for example, has a specific legislation covering the protection and welfare of animals, including fish, the Animal Welfare Act, https://www.legislation.gov.uk/ukpga/2006/45/contents, 2006 (accessed on 10 March 2025). This legislation acknowledges the sentience of fish and the necessity of ensuring their welfare. This encompasses the provision of optimal living conditions, including a suitable environment allowing swimming and natural behavior, as well as the assurance of good water and food quality, healthcare, and the prevention of suffering. In addition, it includes standards for the sale and transportation of fish, addressing the handling and care of animals, as well as transportation requirements, including duration, ventilation, temperature, and adequate space.

In the USA, the Animal Welfare Act (AWA), https://www.nal.usda.gov/animal-health-and-welfare/animal-welfare-act (accessed on 7 March 2025), is the primary federal legislation that requires adequate housing, feeding, and health conditions for warm-blooded animals, excluding fish. However, other initiatives address the welfare of fish, including ornamental species, such as the Lacey Act (http://www.gpo.gov/fdsys/pkg/USCODE-2010-title16/pdf/USCODE-2010-title16-chap53-sec3371.pdf) (accessed on 6 March 2025). This act controls the transport of non-native species (such as animals that have been captured illegally) between states, indirectly protecting them from inappropriate practices. In addition, the American Fisheries Society (AFS), the American Institute of Fishery Research Biologists (AIFRB), and the American Society of Ichthyologists and Herpetologists (ASIH) worked together to produce a guide called ‘Guidelines for the Use of Fishes in Research (https://fisheries.org/policy-media/science-guidelines/guidelines-for-the-use-of-fishes-in-research/)’ (accessed on 6 May 2025). This guide explains how fish should be used in research in an ethical way. Although its applicability is limited to the ornamental fish trade, the guide contains many recommendations for fish welfare, health, maintenance, and handling.

From an international perspective, the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) (https://cites.org/eng/disc/text.php) (accessed on 5 May 2025) is an international agreement that aims to protect animals and plants by regulating international trade. It prevents species from becoming extinct and overexploitation, and it makes sure that trade is managed in a way that considers both conservation and sustainability. However, it does not directly address animal welfare. Some types of ornamental fish are protected by CITES. These include the Hypancistrus zebra, which cannot be exported for commercial purposes. Furthermore, the World Organization for Animal Health (OIE) is in charge of setting international standards for the health of aquatic animals. It does this through the Aquatic Animal Health Code (https://rr-europe.woah.org/app/uploads/2020/08/oie-aqua-code_2019_en.pdf), (accessed on 7 May 2025) which contains recommendations for the welfare of farmed fish. These include how they should be handled and transported. Although these recommendations for improving fish welfare do not involve ornamental fish, they could be used as a guide in this sector.

Many countries have their own animal welfare legislation, which may include such aquatic animals, but the implementation and supervision of these laws vary considerably between countries and even states within countries. In this regard, several factors may contribute to these gaps in legislation and its supervision. The prevalence of informal trade—which frequently occurs without registration and in disparate locations—is one main factor rendering supervision a challenging endeavor (Figure 2). Furthermore, a lack of adequate knowledge about optimal handling practices in terms of fish welfare is common among professionals involved in the ornamental fish trade. However, there has been a notable increase in awareness of fish welfare in recent decades, including in ornamental trade [1]. Nevertheless, the development, implementation, and supervision of initiatives to create specific guidelines and laws regarding the welfare of these aquatic animals remain a necessity throughout the entire ornamental fish chain.

6. Initiatives Promoting Fish Welfare in the Ornamental Trade

Although fish welfare in the ornamental trade has largely been neglected and there is a clear lack of information, some initiatives have recently emerged to help change this scenario. For instance, the Australian initiative For Fish (https://forfish.com.au/rehome-adopt-fish/) (access on 7 May 2025) is dedicated to improving aquatic animal practices and supporting aquatic animal caregivers to promote animal health and welfare through a scientific and evidence-based approach. This initiative helps with the adoption of pet fish, trying to find a new home for these aquatic animals and/or equipment used to take care of them, providing continued care and reducing the waste load by refurbishing and recycling aquatic equipment. Although it is a very interesting initiative, its website appears to be currently offline, and we were unable to locate its social media accounts. As such, to the best of our knowledge, there is no publicly available detailed information on the measurable impact of its actions, such as examples of rehabilitated or rehomed fish, or the extent of its outreach efforts on social media. Thus, we cannot even be certain whether this initiative is still active, which is unfortunate.

Another interesting initiative is the Brazilian Betta Conscience (https://bettaconscience.wordpress.com/) (was accessed on 6 May 2025), which seeks to raise awareness among aquarists about how to care for betta fish, goldfish, and other aquatic animals, as well as disseminating good information on how to provide the best quality of life for them. This initiative aims to change people’s thinking that fish are just ornaments by promoting awareness, conducting fish rescue in situations of mistreatment or inadequate conditions, supporting their physical and behavioral rehabilitation, and facilitating their adoption. For example, a betta named Flame, rescued with chronic self-mutilation behavior, was adopted into a 50 L paludarium and showed significant tail recovery, according to the website. Although the initiative has over 5000 followers and nearly 5000 likes on its Facebook page, as well as more than 1400 followers on Instagram, there have been no new posts since 2022, raising concerns about whether it remains active.

Therefore, while these initiatives provide valuable localized support, questions remain regarding their scalability and long-term sustainability. Many operate with limited resources and reach, which can hinder broader visibility and impact. Moreover, their potential to influence consumer behavior—particularly in terms of promoting more ethical purchasing decisions—relies heavily on public engagement, educational outreach, and integration with mainstream communication channels. Increasing their scalability and influence likely depends on enhanced collaboration with academic institutions, support from regulatory bodies, and integration with larger public education campaigns. Exploring ways to expand their visibility and scale could significantly enhance their role in improving ornamental fish welfare.

Another important initiative is the Ornamental Aquatic Trade Association (OATA) (https://ornamentalfish.org/) (accessed on 7 May 2025), a UK organization that establishes standards for good practice in the ornamental aquaculture trade (including breeding, transport, and sale), thereby promoting the welfare of animals in this sector. Furthermore, the OATA provides guidance and educational resources about the maintenance and care of aquaria and fish, including workshops on diverse topics such as fish biology and advanced aquarist techniques. It also disseminates information through newsletters on recent research and trends in ornamental aquaculture, besides offering technical assistance from specialists in the field who can address specific challenges encountered by aquarium hobbyists. In this way, the OATA promotes the dissemination of information and awareness among both hobbyists and professionals in the trade, emphasizing the importance of ethical practices to ensure fish welfare. In addition to its educational efforts, the OATA plays an active role in international regulatory discussions, such as those held by CITES, where it advocates for evidence-based policies that support sustainable ornamental fish trade. The organization also collaborates with scientific institutions to combat destructive practices, like cyanide fishing, by funding research into detection methods, and its training programs help to professionalize the industry and raise welfare standards through certified instruction.

Besides these, there are other initiatives such as online forums and private groups on social media pages (e.g., Facebook) facilitating discussions between aquarists, sharing experiences, and helping people to improve fish conditions in home aquaria or even to rescue and rehome pet fish. Such private social media groups also facilitate fish, aquatic plant, and equipment donations through posts. Some of them seem to be very active, ranging from a few thousand to tens of thousands of members making posts promoting important discussions to improve the life quality of fish and helping to donate and adopt individuals from several different ornamental fish species. The prohibition of fish selling can be found among the rules of some of these groups, which emphasizes their aim of rehoming fish.

All these initiatives have arisen in response to critical needs within the ornamental fish sector. Among the most urgent issues are the widespread lack of public awareness about fish sentience and welfare requirements, the normalization of poor husbandry practices reinforced by the common ‘disposable’ view of these animals, and the absence of clear guidelines for responsible ownership, as already discussed (Figure 2). The neglect of these issues often results in inadequate conditions in home aquariums or public tanks, the frequent abandonment of pet fish, and preventable suffering. Therefore, initiatives like these are essential to fill these gaps, foster more ethical treatment of aquatic animals, and promote long-term improvements in both public perceptions and animal care standards. These efforts are crucial in addressing systemic weaknesses in the ornamental aquatics field. The lack of formal education or adequate training for aquarists, the inconsistent application of welfare standards across different regions, and the commercial emphasis on aesthetics over animal health and welfare all contribute to a trade environment where the quality of life of fish is often secondary. By providing reliable knowledge, practical resources, and community engagement, these initiatives certainly play a vital role in transforming current practices and encouraging a shift toward more responsible and compassionate care for ornamental fish.

7. Rethinking Terminology: From “Ornamental” to “Pet” Fish

The terminology used in the aquarium trade is not merely semantic—it carries a conceptual weight that can influence how fish are perceived and treated by the public, retailers, and even policy makers. The term “ornamental fish”, though widely adopted, frames these animals as decorative objects, reinforcing a perception of them as passive and replaceable elements of interior design. This framing may unintentionally undermine efforts to recognize their sentience and promote their welfare. In contrast, the term “pet fish” emphasizes their role as companion animals, highlighting their capacity for sentience, behavioral complexity, and the need for appropriate care. This terminology also aligns with a growing body of literature, contributing to improved ethical standards in the trade and the keeping of aquatic animals [22,30,32,73]. Referring to these aquatic animals as “pets” also helps to shift public perception toward greater moral responsibility, as is typically extended to more traditional companion animals like dogs and cats. It is worth mentioning that we adopt a broad definition of “pet,” encompassing not only companion animals in the traditional sense, but also those kept in human-controlled environments for aesthetic or decorative purposes, such as those found in medical or dental office aquariums, for example.

As already argued in this review, a growing body of scientific evidence indicates that fish are sentient vertebrates capable of experiencing pain [3,5,6,8,9], in addition to other negative affective states [5,13,14], which warrants their inclusion in animal welfare frameworks alongside other vertebrate species. Therefore, adopting terminology that reflects this understanding is an important step toward shaping more responsible practices across the ornamental trade, care, and regulation of these animals. While the term “ornamental fish” remains dominant in commercial and regulatory contexts, we then advocate for a progressive shift in discourse—especially in scientific and educational settings—toward the use of “pet fish” when referring to animals kept in homes.

8. Conclusions

The ornamental fish trade presents significant welfare challenges for such aquatic animals—from the capture and transportation phases to their final care. Stressors such as inadequate water quality, improper handling, and overcrowding compromise the health and welfare of fish, often worsened by a lack of understanding among those in the trade and hobbyists alike. The absence of strong legislation and supervision further hinders practical improvements in animal welfare in this trade, leaving many fish vulnerable to poor and stressful conditions. However, the emergence of initiatives has demonstrated a growing recognition of the need to improve welfare practices in the ornamental fish trade. These efforts, combined with greater public awareness and scientifically well-founded guidelines, can foster meaningful change. To ensure lasting improvements, it is crucial to develop targeted legislation, promote education across all levels of the trade, and encourage a shift in perception—recognizing ornamental fish as sentient pets deserving of the same care and respect as other companion animals. In this sense, rethinking terminology—such as adopting “pet fish” instead of “ornamental fish”—may further support a more welfare-centered view. By integrating ethical practices into the ornamental fish industry, we can significantly enhance the welfare of these aquatic animals and set a standard for responsible aquarism.