Reproduction of Ichthyophthirius multifiliis (Ciliata, Ophryoglenidae)

A case of reproduction of Ichthyophthirius multifiliis in the superficial tissues of larvae and fry of Amur wild carp is described. At a temperature of water from 28 to 29 degrees trophonts of Ichthyophthirius encysted on fishes. Inside cysts repeated cell division occurred but this process did not result in swarm spores formation. Later on with the increase of temperature to 29.5--31.5 degrees cysts degenerated.     

Reproduction and spawning behavior of the climbing perch Anabas testudineus (Perciformes, Anabantidae) in an aquarium

Results of study of the spawning and reproductive behavior of the climbing perch Anabas testudineus in an aquarium are presented. Main specific features of reproduction of this species are revealed. In the performed experiments, climbing perches did not build a nest, did not prepare a spawning substrate, and did not show any forms of parental care. The pre-spawning and spawning behavior of the climbing perch is described, and fecundity and gonadosomatic index are determined. It is shown that intermittent spawning is typical of these fish. Mating system of the climbing perch is either polygamy or promiscuity. Sexual dimorphism in the climbing perch was not found. The eggs of the climbing perch have positive buoyancy and belong to the really pelagic type, which is rare for freshwater fish. Infanticide is a common phenomenon for the climbing perch. Breeding of the given species under aquarium conditions can be exercised without artificial hormonal stimulation, at different sex ratio, and under conditions of stocking density considerably exceeding standard aquacultural recommendations. The main specific features of reproduction of the climbing perch are discussed in relation to evolution of parental care in labyrinth fishes.     

Microbial diversity and potential pathogens in ornamental fish aquarium water

Ornamental fishes are among the most popular and fastest growing categories of pets in the United States (U.S.). The global scope and scale of the ornamental fish trade and growing popularity of pet fish in the U.S. are strong indicators of the myriad economic and social benefits the pet industry provides. Relatively little is known about the microbial communities associated with these ornamental fishes or the aquarium water in which they are transported and housed. Using conventional molecular approaches and next generation high-throughput amplicon sequencing of 16S ribosomal RNA gene hypervariable regions, we characterized the bacterial community of aquarium water containing common goldfish (Carassius auratus) and Chinese algae eaters (Gyrinocheilus aymonieri) purchased from seven pet/aquarium shops in Rhode Island and identified the presence of potential pathogens. Our survey identified a total of 30 phyla, the most common being Proteobacteria (52%), Bacteroidetes (18%) and Planctomycetes (6%), with the top four phyla representing >80% of all sequences. Sequences from our water samples were most closely related to eleven bacterial species that have the potential to cause disease in fishes, humans and other species: Coxiella burnetii, Flavobacterium columnare, Legionella birminghamensis, L. pneumophila, Vibrio cholerae, V. mimicus. V. vulnificus, Aeromonas schubertii, A. veronii, A. hydrophila and Plesiomonas shigelloides. Our results, combined with evidence from the literature, suggest aquarium tank water harboring ornamental fish are an understudied source for novel microbial communities and pathogens that pose potential risks to the pet industry, fishes in trade, humans and other species.     

Invasive aquarium fish transform ecosystem nutrient dynamics

Trade of ornamental aquatic species is a multi-billion dollar industry responsible for the introduction of myriad fishes into novel ecosystems. Although aquarium invaders have the potential to alter ecosystem function, regulation of the trade is minimal and little is known about the ecosystem-level consequences of invasion for all but a small number of aquarium species. Here, we demonstrate how ecological stoichiometry can be used as a framework to identify aquarium invaders with the potential to modify ecosystem processes. We show that explosive growth of an introduced population of stoichiometrically unique, phosphorus (P)-rich catfish in a river in southern Mexico significantly transformed stream nutrient dynamics by altering nutrient storage and remineralization rates. Notably, changes varied between elements; the P-rich fish acted as net sinks of P and net remineralizers of nitrogen. Results from this study suggest species-specific stoichiometry may be insightful for understanding how invasive species modify nutrient dynamics when their population densities and elemental composition differ substantially from native organisms. Risk analysis for potential aquarium imports should consider species traits such as body stoichiometry, which may increase the likelihood that an invasion will alter the structure and function of ecosystems.     

Aquarium und Museum für Fischzucht, 1906–1937 in Brüssel,Belgien

In the beginning of last century an aquarium opened in Brussels where besides fishes also a collection of amphibians and reptiles was shown to the public. A small museum was also included. This aquarium was started with the aim just to show freshwater fishes but shortly after the opening also marine species were part of the collection.Curious inhabitants of Brussels who wanted to get acquainted with the unknown animal world and people who were interested in the scientific aspects of fishes, pisciculture, marine life and freshwater world found what they were looking for in the small aquarium and museum. Shortly after the inauguration it was described as ‘…a useful aquarium not only for the scientist who looks for information about all facets of live in water but also for the average visitors who want to get new impressions and enjoys the silence but also want to learn something. Families and schools as well have the possibility to let children and students learn about animals in a total new way’. A few renowned specialists and hydro biologists gave support but the aquarium had to face different problems and the interest of the public dropped off. A short time before World War II the aquarium was closed.     

Where are they all from? – sources and sustainability in the ornamental freshwater fish trade

The global trade in ornamental fish involves c. 125 countries worldwide and is worth c. US $15–30 billion each year. This total is dominated (90%) by freshwater fishes, most of which are sourced from breeding facilities located in developing countries, typically in Asia or South America, but also in Israel, USA and Europe. Some fish are still obtained from natural (wild) sources, but the exact percentage of wild-caught fish is difficult to quantify given a lack of reliable data. Although c. 1000 species of freshwater fishes are widely available (from a total of > 5300 on sale), the most dominant freshwater fishes in the market comprise only 30 species from the orders Cyprinodontiformes, Perciformes, Characiformes and Siluriformes. In this perspectives review paper, illustrative example case studies of wild-fish collecting (Barcelos and Rio Xingu, Brazil) and breeding projects (Java, Indonesia) are described. In addition, wild-collecting expeditions to West Papua, Indonesia are discussed, focused on discovering novel species of rainbowfish (Melanotaeniidae) for breeding in captivity. Sustainability of the aquarium industry is considered in its broadest sense. The aquarium industry has been portrayed as both a major threat to natural ecosystems, but also as being part of the solution in terms of helping to maintain species when they have gone extinct in the wild or offering an income to impoverished citizens who might otherwise engage in much more destructive practices.     

Understanding the United Kingdom marine aquarium trade – a mystery shopper study of species on sale

In this study, we conducted a unique survey of marine ornamental fishes appearing in UK retail stores, as well as a review of government trade statistics, with the aim to significantly strengthen the evidence-base in support of future management initiatives. Fifty marine aquarium retailers were visited. A total of 380 marine aquarium fish species (4926 individuals), from 48 families were recorded with the largest proportion of individuals belonging to the families Pomacentridae, Acanthuridae, Apogonidae, Labridae, Pomacanthidae, Gobiidae and Labridae. The majority of fishes for sale (91% of species) originated from the Indo-Pacific Ocean, with only a small number (9% of species) derived from the Atlantic Ocean. However, exact sources of individual species were unclear and poorly documented. Government trade statistics revealed that the ornamental reef-fish trade in the UK grew markedly between 1996 and 2008 with a rapid acceleration in 2003–2004. However, imports have declined since 2008 and amounted to less than 305,000 kg in 2017 with an economic value of UK £3 million (c. US $3.8). Recent trade data (2017) identify Indonesia, USA, Philippines and the Maldives as the most important countries in terms of imports to the UK. The UK is an important exporter of wild-caught fishes via trans-shipment, but also production of tank-reared animals. Several species observed for sale in the UK have been designated by the IUCN and CITES as being of conservation concern, although all these animals are thought to have been captive-reared.     

Barcoding and border biosecurity: identifying cyprinid fishes in the aquarium trade

Background

Poorly regulated international trade in ornamental fishes poses risks to both biodiversity and economic activity via invasive alien species and exotic pathogens. Border security officials need robust tools to confirm identifications, often requiring hard-to-obtain taxonomic literature and expertise. DNA barcoding offers a potentially attractive tool for quarantine inspection, but has yet to be scrutinised for aquarium fishes. Here, we present a barcoding approach for ornamental cyprinid fishes by: (1) expanding current barcode reference libraries; (2) assessing barcode congruence with morphological identifications under numerous scenarios (e.g. inclusion of GenBank data, presence of singleton species, choice of analytical method); and (3) providing supplementary information to identify difficult species.

Methodology/Principal Findings

We sampled 172 ornamental cyprinid fish species from the international trade, and provide data for 91 species currently unrepresented in reference libraries (GenBank/Bold). DNA barcodes were found to be highly congruent with our morphological assignments, achieving success rates of 90–99%, depending on the method used (neighbour-joining monophyly, bootstrap, nearest neighbour, GMYC, percent threshold). Inclusion of data from GenBank (additional 157 spp.) resulted in a more comprehensive library, but at a cost to success rate due to the increased number of singleton species. In addition to DNA barcodes, our study also provides supporting data in the form of specimen images, morphological characters, taxonomic bibliography, preserved vouchers, and nuclear rhodopsin sequences. Using this nuclear rhodopsin data we also uncovered evidence of interspecific hybridisation, and highlighted unrecognised diversity within popular aquarium species, including the endangered Indian barb Puntius denisonii.

Conclusions/Significance

We demonstrate that DNA barcoding provides a highly effective biosecurity tool for rapidly identifying ornamental fishes. In cases where DNA barcodes are unable to offer an identification, we improve on previous studies by consolidating supplementary information from multiple data sources, and empower biosecurity agencies to confidently identify high-risk fishes in the aquarium trade.     

Current status of sperm cryopreservation in biomedical research fish models: zebrafish, medaka, and Xiphophorus

Aquarium fishes are becoming increasingly important because of their value in biomedical research and the ornamental fish trade, and because many have become threatened or endangered in the wild. This review summarizes the current status of sperm cryopreservation in three fishes widely used in biomedical research: zebrafish, medaka, and live-bearing fishes of the genus Xiphophorus, and will focus on the needs and opportunities for future research and application of cryopreservation in aquarium fish. First, we summarize the basic biological characteristics regarding natural habitat, testis structure, spermatogenesis, sperm morphology, and sperm physiology. Second, we compare protocol development of sperm cryopreservation. Third, we emphasize the importance of artificial fertilization in sperm cryopreservation to evaluate the viability of thawed sperm. We conclude with a look to future research directions for sperm cryopreservation and the application of this technique in aquarium species.     

The response of female guppies, Poecilia reticulata, to chemical stimuli from injured conspecifics

Predation is an important component of the life history and behavior of many fish. In some species of teleost fishes, conspecifics respond to chemical stimuli from injured conspecifics by displaying a fright response, such as increased cohesion of schooling. The purpose of this experiment was to investigate whether female guppies, Poecilia reticulata, display a fright response when exposed to a filtered extract made from wounded conspecifics. The schooling behavior of female guppies was observed for ten minute periods for each of three treatments: baseline treatment (no substances added to the aquarium water), sham treatment (distilled water added to the aquarium water), and alarm treatment (fish extract added to the aquarium water). Female guppies responded with a fright reaction when exposed to a filtered extract prepared from wounded conspecifics; female swam in a more cohesive school during the alarm treatment than they did in either the baseline or sham treatments. The guppy fright reaction response indicates that the fish extract is recognized by conspecifics. This revised version was published online in August 2006 with corrections to the Cover Date.     

Etude comparative de la densite de groupes de poissons cavernicoles et epiges (characidae,cyprinidae, clariidae)

The group density of four species of cave fishes (Caecobarbus geertsi, Barbopsis devecchii, Astyanax gen. and Uegitglanis zammaranoi) and of two taxonomically related epigean species (Barbus conchonius and Hyphessobricon scholzei) was measured tridimensionally in an experimental aquarium, using a video recorder and a mirror inclined at 45° placed on top of the aquarium. The experiments were conducted in dim red light. The illumination was continuous in the case of cave fishes. For the epigean forms a 12/12 LD cycle was superimposed using dim achromatic sources. The relative positions of individuals within their own specific group were registered hourly during a week (168 h). Results show that in cave forms, the mean density of groups falls within the theoretical limits of random distribution values in all cases, whereas epigean species display a non-random aggregation tendency.     

Invasion risks posed by the aquarium trade and live fish markets on the Laurentian Great Lakes

International trade is an important mechanism for global non-indigenous species introductions, which have had profound impacts on the biodiversity of aquatic ecosystems including the Laurentian Great Lakes. The best-documented vector by which non-indigenous species have entered the Great Lakes is ballast water discharged by transoceanic ships. A variety of potential alternative vectors exist, including the intentional release of aquarium or food organisms. To assess whether these vectors pose a significant invasion risk for the Great Lakes, we surveyed fish sold live in markets and fish, mollusks and macrophytes sold in pet and aquarium stores within the Great Lakes watershed. We evaluated invasion risk using information on species’ thermal tolerance, history of invasion elsewhere, and potential propagule loads as indicated by frequency of occurrence in shops. Our research suggests that both the aquarium industry and live fish markets represent potential sources of future invaders to the Great Lakes, including several aquarium fishes and macrophytes, as well as Asian carp species sold in fish markets. Currently, few regulatory mechanisms exist to control these potential vectors.     

Ecology of the River Dolphin (Platanista gangetica) in the Upper Brahmaputra

There are nearly 200 species of aquatic vertebrates, almost exclusively fishes, in the Brahmaputra River System. This faunal composition includes not only a wide variety of food-fishes, but also about 50 varieties of aquarium fishes. The most spectacular animal in the Brahmaputra is undoubtedly the river dolphin, Platanista gangetica. The population of many species, particularly of the dolphin, is in steady decline. River dolphins, mostly juveniles, often entangle themselves in gill and drift nets, while feeding on trapped fishes. Proper implementation of Indian Fisheries Act, especially a total ban on destructive nets and on killing of brooders and juveniles by explosives and poisoning should be strictly implemented. Poor communication facilities in remote riverbank areas and lack of funds are two important reasons for the slow progress of the conservation of river dolphin and this endangered species is now on the verge of extinction. The anthropogenic activities and their impact on the habitat of river dolphin are discussed.     

Highly Repetitive Object Play in a Cichlid Fish (Tropheus duboisi)

Whether play occurs in fishes has long been a contentious issue, but recent observations document that social, object, and locomotor play can all be found in some species of teleosts. However, quantitative studies and those documenting individual differences are rare. We recorded hundreds of occurrences of an unusual behavior in three male Tropheus duboisi. The target behavior of attacking and deflecting an object that rapidly returned to its upright position not only fit the criteria for play behavior, but differed quantitatively and qualitatively among the individuals. This behavior has not been observed in other species of cichlids and other kinds of fishes. The presence or absence of food or other fish either within the aquarium or visible in an adjacent aquarium had no marked or consistent effect on the occurrence of the behavior. Various explanations for the origin and function of the behavior are discussed.     

Does food quality influence thermoregulatory behavior in the intertidal fish Girella laevifrons?

Algal and invertebrate species are less abundant towards higher zones of the intertidal, where the greatest variations in physical environmental conditions occur. Mobile predators such as fishes that inhabit high intertidal rockpools are thus exposed to wide variations in physical conditions and to a low abundance and quality of food. We used an aquarium with a temperature gradient in the laboratory to assesed whether dietary quality differences modify temperature preferences of Girella laevifrons, one of the most abundant transitory fishes inhabiting rocky shores along the coast of Chile. Our results indicate that food quality clearly modifies temperature preferences in this species. Animals fed on high quality bivalves selected intermediate temperatures (16–18°C) while those fed on lower quality algae selected lower temperatures (10–12°C). Control fish not subjected to the temperature gradient did not select portions of the aquarium differentially. The thermal selectivity of G. laevifrons in relation to the optimization of digestive processes and mechanisms of energy conservation are discussed.     

Analysis of the marine ornamental fish trade at Ceará State, northeast Brazil

Brazil is one of the leading exporters of ornamental fishes, mostly freshwater; however, monitoring of the trade is nearly non-existent in the country. This paper provides an initial assessment of a new venture, the marine aquarium fish trade at Ceará State, northeast Brazil, aiming to document the species traded, to provide preliminary estimates of numbers of specimens traded, and to identify priorities in data collection and monitoring. A total of 143 species and 199 304 fishes were traded. From the total, 109 species were native and represented 84% of the fishes traded. Thirty-four exotic species figured on the permits and amounted to nearly 16% of the exports; however, most of them consist of misidentified native species. Nearly 90% of the fish trade was directed to the international market. Official figures represent an underestimation of the total number of captured specimens.     

Immune response of fishes to ciliates

Ciliates are highly evolved protists comprising a phylum of diverse species, many of which are opportunistic or obligate parasites. Ciliates parasitic to fish consist of salt and freshwater forms with endo- or ectoparasitic modes of infection. Some of the more commonly encountered genera include Chilodonella, Brooklynella, Ophryoglenina, Ichthyophthirius, Cryptocaryon, Uronema, Tetrahymena, Epistylus, and Trichodina. Species range from obligate parasites and commensals to opportunistic, facultative forms. Some parasitic ciliates are highly pathogenic and fishes in closed environments such as aquaria and farm ponds are particularly susceptible to high mortalities. Nevertheless, fish have evolved an immune system capable of mounting an effective protective response against parasite challenge. Much of the experimental research on immunity against ciliates has been carried out with Ichthyophthirius multifiliis, on obligate parasite that invades surface epithelia of virtually all freshwater fish species. Interest in the immune response against I. multifiliis stems from the fact that convalescent fish become resistant to subsequent challenge (suggesting the possibility of immunoprophylaxis), and the need to curtail severe losses caused by this parasite in intensively farmed fishes. Furthermore, I. multifiliis has proven to be a useful experimental model because it is amenable to study under laboratory conditions. In this review cellular and humoral factors involved in both innate and acquired immunity against ciliates are covered and include natural killer cells, phagocytic cells, and antibody responses. Current ideas on the mechanisms of antibody-mediated cutaneous immunity against I. multifiliis are discussed and approaches toward the development of vaccines against this and other ciliate parasites are presented.     

The damselfishes (Pisces: Osteichthyes: Pomacentridae) of Peninsular Malaysia and Singapore: systematics,ecology and conservation

Damselfishes (Pomacentridae) are among the most common of reef fishes in tropical seas, comprising 320 species in all, with 268 species alone in the Indo-West Pacific regions. 15 genera (Abudefduf, Amblyglyphidodon, Amphiprion, Chelioprion, Chromis, Chrysiptera, Dascyllus, Pristotis, Dischistodus, Hemiglyphidodon, Neoglyphidodon, Neopomacentrus, Plectroglyphidodon, Pomacentrus, Stegastes) and at least 39 species inhabit the waters of Peninsular Malaysia and Singapore. They are important ecologically because many species are extremely abundant in reefs, and also economically, as several are collected in large numbers for the lucrative aquarium trade. This demand has led to some fishermen using destructive methods in obtaining the fishes, to the point that original standing populations may not be recoverable. This threat poses a need for conservation of the reefs. The present study based primarily on fishes collected from the waters of Singapore and specimens from the Zoological Reference Collection at the National University of Singapore, will serve the dual purpose of establishing a current species list for Malaysia and Singapore, and to update and clarify the local taxonomy of the group. An annotated list (with localities) is provided of the known or reported species to aid studies on reefs.     

Camallanus cotti Fujita, 1927 (Nematoda, Camallanoidea) in ornamental aquarium fishes: pathology and morphology

The pathology induced by the nematode Camallanus cotti in the aquarium fishes Beta splendens (beta fish) and Poecilia reticulata (guppy) consisted of gross and microscopic lesions, the former characterized by abdominal swelling with reddish parasites protruding from the anus in both fish hosts and the latter, similar in the beta fishes and guppies, by hemorrhage, congestion, edema, a few glandular elements, and extensive erosion areas in the rectum mucosa, with a marked thickening of the wall and absence of inflammatory infiltrate. Lesions were associated with the presence of several worms attached to the wall or free in the rectal lumen. This is the second reference of the parasite in Brazil and the first report of pathological findings related to this nematode species that is also briefly redescribed and illustrated for the first time on the basis of Brazilian samples.     

Revealing the appetite of the marine aquarium fish trade: the volume and biodiversity of fish imported into the United States

The aquarium trade and other wildlife consumers are at a crossroads forced by threats from global climate change and other anthropogenic stressors that have weakened coastal ecosystems. While the wildlife trade may put additional stress on coral reefs, it brings income into impoverished parts of the world and may stimulate interest in marine conservation. To better understand the influence of the trade, we must first be able to quantify coral reef fauna moving through it. Herein, we discuss the lack of a data system for monitoring the wildlife aquarium trade and analyze problems that arise when trying to monitor the trade using a system not specifically designed for this purpose. To do this, we examined an entire year of import records of marine tropical fish entering the United States in detail, and discuss the relationship between trade volume, biodiversity and introduction of non-native marine fishes. Our analyses showed that biodiversity levels are higher than previous estimates. Additionally, more than half of government importation forms have numerical or other reporting discrepancies resulting in the overestimation of trade volumes by 27%. While some commonly imported species have been introduced into the coastal waters of the USA (as expected), we also found that some uncommon species in the trade have also been introduced. This is the first study of aquarium trade imports to compare commercial invoices to government forms and provides a means to, routinely and in real time, examine the biodiversity of the trade in coral reef wildlife species.