Aquarium Pet Research Articles

Ornamental fish in the South African pet shop trade: potential risk to natural aquatic ecosystems

AbstractThe aquarium pet trade is one of the leading pathways for the introduction of invasive species into natural ecosystems. In 2018, we surveyed pet shops across South Africa to obtain a checklist of ornamental fish species in the aquarium pet shop trade and to assess their invasion potential using sourced data (e.g., natural environment, native range, introduction status, impact status and climatic zone). We evaluated selected common aquarium fish species with high invasion potential according to previous invasion history. We highlighted the need for the development of a management strategy for the aquarium pet trade in South Africa. We identified 312 fish species belonging to 77 families and 182 genera. Most pet shops were in Gauteng Province (n = 38), with few in Limpopo Province (n = 3). Gauteng had the highest number of fish species (n = 271), while North West Province had the lowest number (n = 95). Pet shops were dominated by freshwater species (68%), followed by marine species (22%), while the origin of 30 species (10%) was transitional aquatic ecosystems. Most freshwater taxa were native to South America and Asia, while most marine species were from the Pacific and Indo-Pacific Oceans. Most (88%) species were tropical, 10% subtropical, and 1% temperate. Several (n = 28) species had more than 50% frequency of occurrence, representing the most popular ornamental fishes. Several (n = 13) species are invasive in South Africa and other parts of the world. The system of importation of ornamental fish in South Africa is not clear. Although there is a recommendation that these importations must be regulated according to the whitelist and blacklist in South Africa, it is not clear how this is implemented in practice. We demonstrated a high risk of alien fish species introduction in South Africa through the aquarium pet shop trade.

The Sailfin Catfish (Pterygoplichthys spp.) as a non-native aquarium pet: assessment of the potential distribution and public perception

The Sailfin Catfish (Pterygoplichthys spp.) as a non-native aquarium pet: assessment of the potential distribution and public perception

Invasion potential of the aquarium pet snail Planorbella trivolvis in India: impact of certain abiotic and biotic factors.

Planorbella trivolvis (ramshorn snail) is one of India's most extensively sold exotic aquarium pet snails. The unintentional or deliberate release of P. trivolvis may result in the colonisation and establishment as an invasive snail in freshwater ecosystems. However, the successful invasion of P. trivolvis will depend on several abiotic and biotic factors of the concerned freshwater ecosystem. We have assessed the possibility of overcoming the opposing factors in P. trivolvis invasion through laboratory-based experiments and examined the effects of household-derived pollutants on egg hatchability, adult survivability and fecundity, and temperature (15 to 35°C) on growth, sexual maturity, and reproduction. Additionally, we have evaluated the potential of native predators as biotic resistance to invasion by prey-choice experiment. The results indicated that egg hatchability, adult survivability, and fecundity were reduced with increasing pollutant concentration. However, the same traits did not differ from a native freshwater snail, Indoplanorbis exustus. The fecundity of P. trivolvis increased with increasing body size, but no considerable differences at different temperature levels suggest a wide range of adaptation to temperature. Faster growth and the requirement of comparatively few days to attain sexual maturity were observed in the higher temperatures. The native predators, Glossiphonia weberi and Diplonychus rusticus, avoided P. trivolvis as prey over the alternative prey snails in most instances, suggestingthe masking ofbiotic resistance against the colonisation. Our observations indicate that the chance dispersal of P. trivolvis from household or commercial aquaria may lead to a possible invasion of freshwater ecosystems under suitable conditions.

Feeding habit and intensity of Periophthalmus variabilis caught from some coastal provinces in the Mekong Delta, Vietnam

Dusky-gilled mudskipper Periophthalmus variabilis, a member of the family Gobiidae, is a potential aquarium pet in the Mekong Delta (MD), Vietnam; however, data on its feeding habit and intensity has been limited. Therefore, this study aims to evaluate the relative gut length (RGL) and gastro-somatic index (GI) of Periophthalmus variabilis in order to determine the feeding habit and intensity of this mudskipper and its variation regarding sex, size, season, site, and their interaction. One thousand one hundred seventy mudskipper samples were collected monthly in four locations: Duyen Hai-Tra Vinh, Tran De-Soc Trang, Hoa Binh-Bac Lieu, and Dam Doi-Ca Mau from January 2022 to December 2022. The analysis showed that Periophthalmus variabilis was a carnivorous fish with an average RGL value of 0.52±0.01 SE (<1). In addition, the RGL of this species varied and depended on size, sampling site, season, and the interaction of both size and season with locations. The GI of the mudskipper was 4.27±0.29 SE, indicating that its feeding intensity belonged to the moderate category and varied with size and site but not sex, season, and interactions. These results supplement novel knowledge on its feeding habit and intensity, a basis for researching the aquaculture of Periophthalmus variabilis in MD.

The aquarium pet trade as a source of potentially invasive crayfish species in Serbia

The aquarium pet trade as a source of potentially invasive crayfish species in Serbia

Applying Image Recognition and Tracking Methods for Fish Physiology Detection Based on a Visual Sensor.

The proportion of pet keeping has increased significantly. According to the survey results of Business Next, the proportion of Taiwan families keeping pets was 70% in 2020. Among them, the total number of fish pets was close to 33% of the overall pet proportion. Therefore, aquarium pets have become indispensable companions for families. At present, many studies have discussed intelligent aquarium systems. Through image recognition based on visual sensors, we may be able to detect and interpret the physiological status of the fish according to their physiological appearance. In this way, it can help to notify the owner as soon as possible to treat the fish or isolate them individually, so as to avoid the spread of infection. However, most aquarium pets are kept in groups. Traditional image recognition technologies often fail to recognize each fish’s physiological states precisely because of fish swimming behaviors, such as grouping swimming, shading with each other, flipping over, and so on. In view of this, this paper tries to address such problems and then proposes a practical scheme, which includes three phases. Specifically, the first phase tries to enhance the image recognition model for small features based on the prioritizing rules, thus improving the instant recognition capability. Then, the second phase exploits a designed fish-ID tracking mechanism and analyzes the physiological state of the same fish-ID through coherent frames, which can avoid temporal misidentification. Finally, the third phase leverages a fish-ID correction mechanism, which can detect and correct their IDs periodically and dynamically to avoid tracking confusion, and thus potentially improve the recognition accuracy. According to the experiment results, it was verified that our scheme has better recognition performance. The best accuracy and correctness ratio can reach up to 94.9% and 92.67%, which are improved at least 8.41% and 26.95%, respectively, as compared with the existing schemes.

Unwanted ‘hitchhikers’ of ornamental snails: a case report of digeneans transported via the international pet trade

In the European Union, aquarium pets are organisms intended for closed places (e.g., pet shops, garden ponds, home aquariums). Until April 2021, regulations did not require veterinary inspection of these animals within the EU, although there is a potential risk of such organisms being released into the environment along with their symbiotes or parasites. Currently, a “disease-free” declaration is required, but no aquarium snail pathogen that needs attention in international trade has been included in the list of potential hazards. Here, we intended to check whether molluscs from the pet trade could be a source of parasites. We answered this question by using Anentome helena, a popular commodity in the ornamental pet industry, as a research model. Snail specimens were randomly collected from aquarium pet stocks imported from Bangkok (Thailand) to Warsaw (Poland) in March 2020. In total, three specimens were subjected to histological examination and 27 specimens were autopsied. Histological analysis revealed that one snail was infected with rediae (and the cercariae inside them). Our study is the first to show the presence of digenean larvae in A. helena originating from the ornamental pet industry. The spread of such “hitchhikers” in non-native areas will likely be associated with threats to environmental and public health. Therefore, it is necessary to constantly draw public attention to the possible consequences of releasing ornamental pets into the non-native environment.

Multigene phylogeny of reef lobsters of the family Enoplometopidae (Decapoda: Crustacea)

The reef lobsters of the family Enoplometopidae de Saint Laurent, 1988 are attractive marine aquarium pets but the generic assignments have been controversial. Molecular phylogeny using five genetic markers (three mitochondrial and two nuclear) on 11 of the 12 species known in the family successfully reconstructed a robust phylogenetic tree for the reef lobsters with two well-supported groups. The genus Hoplometopus Holthuis, 1983 is revived but with diagnostic characters revised and H. voigtmanni (Türkay, 1989) should be treated as a synonym of H. holthuisi (Gordon, 1968). Four synapomorphies are identified in Enoplometopidae, including the number of the intermediate and postcervical teeth on the carapace, the shape of abdominal pleura and the spination of the palm of large chelipeds. Fossil calibration and ancestral range reconstruction analyses suggested that reef lobsters had a Tethyan deeper water origin and emerged during the Cretaceous period. Enoplometopus s.s. was relatively primitive, whereas Hoplometopus diverged in the Central Indo-Pacific in the Upper Cretaceous and later crossed the Mediterranean into the Atlantic. Overall the family Enoplometopidae mainly speciated in the Central Indo-Pacific, and actively re-occupied shallow-water habitats and invaded temperate regions.

English

Abstract In the present study, for the first time the Mexican freshwater crayfish reported in the Japanese aquarium pet trade is identified as Cambarellus patzcuarensis. This diagnosis is based on the morphological description of key characters, such as the gastric mill, mandible, and gill, which are also illustrated. Information on the introduction history and legislation of the species in Japan is provided. Mating behaviour of the species was observed under laboratory conditions and is described.

Predicting aquatic invasions in a megadiverse region: Maximum‐entropy‐based modelling of six alien fish species in Malaysia

Abstract There has been a recent increase in the occurrence and proliferation of alien fish species in rivers, lakes, and reservoirs of Malaysia, posing a significant risk to native biodiversity. This increase has been largely caused by the unmanaged aquaculture and aquarium pet trade. At present, very little information is available on the diversity and distribution of alien fish species in freshwater ecosystems of Malaysia, as well as their current and future threats. Using the MaxEnt model, the potential habitat suitability and future invasion ranges of six alien fish species (Cichla ocellaris, Clarias gariepinus, Oreochromis mossambicus, Oreochromis niloticus, Poecilia reticulata, and Pterygoplichthys pardalis) in Peninsular and East Malaysia (Borneo) were determined. All six alien fish species investigated, have high potential to invade eight states in Peninsular Malaysia (Johor, Kelantan, Malacca, Negeri Sembilan, Pahang, Perak, Selangor, and Terengganu), and much of East Malaysia. The results also indicate that alien fish are likely to invade the majority of the 444 protected areas in the country, particularly those located in Sabah and Sarawak, which are known for their high fish diversity and endemism. Minimum temperature of the coldest month (Bio 6) and isothermality (Bio 3) significantly influence potential invasion habitats for all six alien fish species in Malaysia. The country's hot and humid climate makes it ideal for the survival and proliferation of alien species except for P. pardalis. These findings will help conservation planners and managers in identifying areas of high concern for alien freshwater fish species in Malaysia, and to pre‐emptively mitigate and manage their future invasion.

Molecular detection of a non-native hybrid eelgrass, Vallisneria spiralis Linnaeus (1753) × V. denseserrulata Makino (1921), in the southeastern United States

During a genetic survey of Vallisneria americana in the southeastern United States, a non-native hybrid between V. spiralis Linnaeus and V. denseserrulata Makino was detected in eight locations across Florida and Alabama. Although previously reported in Japan, Hungary, and Australia, this is the first documented occurrence of the hybrid in North America. Because natural ranges of both parent species are not sympatric in the wild, it is thought that the hybridization event occurred in aquaria. The presence of both species in the aquarium pet trade also makes the industry a potential source of the introduction in the United States. More extensive sampling will be necessary to determine the full distribution of the hybrid, as well as to evaluate its potential impact on native Vallisneria populations and the aquatic ecosystems they support.

Far from home: Tracking the global ornamental fish trade in endangered zebra loach, Botia striata, from freshwater ecoregion and biodiversity hotspot in India

Countless animals, including threatened species from invertebrates to vertebrates, are the victims of the world’s largest illegitimate business—illicit sales of wildlife. Botia striata (zebra loach) is an endangered freshwater fish endemic to the Western Ghats of India. Because of its distinctive stripes, it is heavily exported and ranks second in the volume of trade in aquarium pets from India. However, maintaining a sustainable aquarium trade is a complex task which depends on the availability of authentic data on the volume of trade, trade routes and the supply chain of the species involved. In this study, therefore, we collected five years of trade data including daily exports of zebra loach from India's international airports to identify the global centers for its trade, its exact traded volume and trade routes. To support artificial breeding programs of zebra loach, the breeding season and size at first maturity were also determined. Using reproductive biology data, the number of individuals traded during the breeding season and the total contribution of immature individuals to the trade were also determined. Results revealed that 265,610 zebra loach were exported from five exit points in India to sixteen different countries (global centers in Asian countries). The greatest number of consignments was from Kolkata, which makes it the top exit point for the zebra loach trade. Singapore is the top importer (73.05%) of zebra loach and thus probably acts as a transit hub for the distribution of zebra loach individuals across the globe. About 60% of the zebra fish were exported during the breeding season suggesting that the global aquarium pet trade may increase the fish’s risk of extinction. Our global maps of trade centers of the study species would serve as “The past as a guide to the future”. The present study indicates that sustainable trade in wildlife can be achieved if laws are enacted and enforced to require information on traded species, support functional artificial breeding programs, include species of conservation concern into CITES appendices and ensure strict enforcement of laws to preserve biodiversity.

The redclaw crayfish: A prominent aquaculture species with invasive potential in tropical and subtropical biodiversity hotspots

AbstractThe redclaw crayfish (Cherax quadricarinatus; hereafter redclaw), native to northern Australia and southern New Guinea, is among the largest freshwater decapods. It matures early and is considered highly prolific as females may lay over one thousand eggs in a single clutch. Despite generally preferring slow‐moving streams in its native range, it has a wide environmental tolerance, making it capable of establishing populations when introduced to a wide range of other conditions and habitats. These biological and ecological features render it a highly suitable and popular species for aquaculture worldwide, being the second most important crayfish species economically (after the red swamp crayfishProcambarus clarkii). Adding to that, its unique coloration fuels demand and value among aquarium enthusiasts, making it attractive for the aquarium pet trade. Today, redclaw is widely translocated (67 countries/territories) and various established wild populations (22 countries) have been reported on every continent except Antarctica. Information on its potential or observed impacts, however, is sparse and often anecdotal. To address this gap, this comprehensive review compiles all available information on this species, covering its taxonomy and description, biology and ecology, native and non‐native ranges accompanied with documented introduction pathways. Built upon these, we conducted biological and socio‐economic classification and species distribution modelling. We reveal a lack of thorough impact assessments for this species despite sufficient indications of major observable impacts at local scales. We call attention to the importance of managing the use of this prominent introduced species in aquaculture and aquarium pet trade.

Online auction marketplaces as a global pathway for aquatic invasive species.

The ornamental aquarium pet trade is a leading pathway for the introduction of aquatic invasive species. In addition to purchasing live organisms in stores, hobbyists are engaging more with alternative informal online marketplaces that enable peer-to-peer selling of aquarium organisms via auctions. Although growing in popularity, little is known regarding the global extent of informal marketplaces, including the taxonomy of species that are traded, their economic value, and the geographic routes by which live organisms are transported. In this study we use an automated web crawler to collect data on completed auctions between 2011 and 2017 from the largest informal market for aquarium hobbyists, AquaBid, to understand the market dynamics and trade flows of the informal retail market online. During the 7-year study period, the AquaBid website facilitated the estimated trade of 539,548 live freshwater animals, 579,700 fish eggs, and 31,431 plant assortments/bunches among 24,409 unique users who collectively placed 444,132 bids on 192,227 auctions, representing a total sale value of $6,015,030 USD. Source (seller) and recipient (buyer) locations of live organisms were distributed across 39 countries but concentrated largely in major cities of the United States and select European and southeast Asian countries. Our study is among the first to quantify geographic routes of live organism transport between specific locations on the landscape and demonstrates the highly diffuse and non-centralized nature of the informal aquarium trade. Evaluating the emerging challenges represented by informal online retail marketplaces is critical to create policy and regulatory solutions that minimize the transport of prohibited invasive species.

Molecular Analysis and Chromosome Mapping of Repetitive DNAs in the Green Terror Andinoacara rivulatus (Cichlidae: Cichlasomatini).

Neotropical cichlids include hundreds of species whose taxonomy has benefited of molecular phylogeny and whose karyotype evolution has been related to the amount and distribution of different classes of repetitive sequences. This study provides the first integrative molecular (cytochrome c oxidase subunit 1 and 16S sequences) and cytogenetic analyses of wild samples of the green terror Andinoacara rivulatus, a cichlid naturally distributed in Ecuador and spread throughout the world as an aquarium pet. Molecular data revealed that sequences of green terror constitute a single monophyletic clade within the genus and allowed species attribution of uncertain samples previously cytogenetically analyzed. Chromosome number (2n = 48) conforms to the general trend observed within neotropical cichlids. However, mapping of different classes of repeated sequences (18S rDNA, 5S rDNA, U1 snDNA and telomeric) revealed the presence of features uncommon among representatives of these fishes, like multiple major rDNA sites, and suggested a recent occurrence of rearrangements (fusion/inversion) in two chromosome pairs.

First report of freshwater atyid shrimp, Caridina formosae (Decapoda: Caridea) as a host of ectosymbiotic branchiobdellidan, Holtodrilus truncatus (Annelida, Citellata)

In recent years, ornamental shrimps gained increasing popularity in the aquarium trade. Unfortunately, they are potential vectors of epibionts, which may be unintentionally introduced to aquaria with imported shrimps. This contribution presents the first report of the occurrence of Holtodrilus truncatus on aquarium freshwater shrimp Caridina formosae. A total of 120 shrimp imported from Taiwan as aquarium pets were examined for the presence of epibionts. Holtodrilus truncatus occurred in 23.3% of shrimps. A total of 29.6% of crustaceans showed signs of damages as a result of H. truncatus activity. The shrimp is not common in the ornamental trade and is not subject to selective breeding. Therefore C. formosae populations available on the market, if not wild-caught, are most likely very similar to those occurring in Taiwanese natural water bodies, where H. truncatus occurs in Neocaridina shrimp. Neocaridina spp. are a known host for this epibiont, and transmission between species might occur in nature as well as in the aquarium trade were densities of animals are often high. The ability of H. truncatus to infect also highly invasive crayfish Procambarus clarkii, might also pose concern for regions where this crustacean is widespread. The actual lack of preventive measures for shrimp epibionts as well as confirmed releases of ornamental crustaceans into new aquatic ecosystems may result in further spread of H. truncatus, a potential new threat to native crustaceans and other epibionts.

The invasive apple snail Pomacea canaliculata in Indonesia: a case study in Lake Rawa Pening, Central Java

The occurrence of the invasive apple snail Pomacea canaliculata in Indonesia was first reported in 1984. The species was introduced as an ornamental aquarium pet. Since then, people have begun to culture the snail in ponds usually adjacent to rice fields. When it was realized that the species multiplied rapidly and was a serious pest, this invasive apple snail had already spread widely. There are many cultural methods of controlling and preventing its distribution, but none are effective in keeping them at non-damaging levels. We mapped the distribution of P. canaliculata in Indonesia from the MZB’s collections as well as literature references and found that the snail invaded almost all large islands, such as Sumatra, Java, Kalimantan, Sulawesi, Maluku, and West Papua. We also studied the impact of P. canaliculata on the native apple snails P. ampullacea, P. scutata, and P. virescens in Lake Rawa Pening (a popular tourism destination) as a case study. The results showed that two species of Pila already disappeared from Lake Rawa Pening. Only P. scutata occurs still in the region and was found alive usually in shallow water and rice fields surrounding the lake. To resolve the problem we recommend that cleaning the lake periodically from the invasive aquatic weed Eichhornia crassipes (known to locals as “eceng gondok”) by a private company and harvesting the weeds for the local small craft industry by the local fishermen could be an alternative measure to reduce the population of the P. canaliculata, as well as collecting P. canaliculata for local food or for feeding ducks. Rearranging the number of fish-pens “karamba” and their location in the lake could be seen as an alternative way also for reducing the population of P. canaliculata, since the snails lay their egg masses on the bamboo stakes of “karamba.” Such rearrangement could make the landscape more attractive for tourism.

Infectious diseases in aquarium ornamental pet fish

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.

Patterns and drivers of aquarium pet discharge in the wild

Abstract Aquarium pets release is an important vector for invasive species establishment in freshwater ecosystems. Here the perceptions and risk behaviors associated to this vector were evaluated using a survey. Portuguese aquarium hobbyists were interviewed through an on-line survey (Google forms) publicized in 9 web sites connected to this hobby (Facebook pages and internet forums). A Pet Propagule Pressure index (PPP), congregating information regarding pet’s popularity and electivity for discharge, was developed and applied in this study, so that relative comparisons can be made among different pet types (taxa). Additionally, non-metric Multidimensional Scaling (nMDS) was applied to pet owner’s data to identify indicator factors associated with risk behaviors and impacts’ awareness. Results indicated that aquarium pet owners usually only have one pet type, most commonly fish or turtles. Only 8% of the owners admit having discharged pets, being more commonly reported the release of only one pet. This risk behavior is connected mainly to the excessive growth of the pet and consequently lack of space in the aquariums. Pet’s discharge occurs until 100 km of distance from owner’s homes, being very common at distances lower than 1 km. The PPP index developed in this study, indicates the pet types with higher risk of discharge were the turtles and the fishes. Pet owner’s awareness regarding the pet discharges impacts in the environment seems to be lower than other risk groups connected to biological invasions in freshwaters, namely anglers. Pet owners most aware of these impacts were associated to higher education levels and higher experience on this hobby. Our study highlights the needs for more environmental education on particular social groups within aquarium pets’ owners, namely those that have started this activity or have lower education levels, to decrease the biological invasion risks associated to this hobby. Additionally, our findings regarding the patterns and drivers of discharge action itself are useful to model risk invasion, as well as for detection, management and control of these species.

Mapping the teaching of aquatic animal veterinary medicine in the European Union and European Free Trade Area

Aquatic animal production is the fastest growing food sector globally. Aquaculture and fisheries are very dynamic sectors in the EU and the number of ornamental aquarium pets is increasing. Veterinarians...