Aquarium Fish Research Articles

Fine Bubble Mixing (FBM) Culture of E. coli: A Highly Cost-effective Middle Scale-size Culture System

A highly cost-effective and easy-to-assemble cultivation system suitable for middle scale-size culturing of bacterial cells is described. In the culture, from a flat-shaped air-stone with large surface area, fine bubbles are generated with a low-cost air pump available in an aquarium fish shop, and cell-agitation and oxygen supply are efficiently conducted by fine bubbles simultaneously. Growth properties of the cells and their saturation density are comparable to those in a conventional culture system. The expression of recombinant protein was revealed to be similar to conventional methods. The system does not require any expensive machines or equipments. In addition, all equipments except plastic flat-shaped airstone are reusable after sterilization. Due to the low cost, the ease to use and multiple cultivations at once, our system may enable to find better culture conditions, to scale-up with ease and to perform timesaving efficient protein production.

Acoustic characterization of seahorse tank environments in public aquaria: A citizen science project

Professional aquarists from nine U.S. public aquaria participated in a citizen science project to characterize ambient noise in marine ornamental aquaria containing seahorses (Hippocampus spp.). Participants collected data on tank design specifications and acoustic recordings from the middle of the water column of each tank surveyed. Ambient noise in aquaria was very variable, ranging in total RMS power from 116.3 to 142.9dB SPL (re: 1μPa), with a mean total RMS power of 126.1±0.8dB. Among tank design specifications: wall material, bottom habitat type, and their interaction had significant effects on total RMS power. Glass tanks were significantly louder than acrylic and concrete tanks, but not fiberglass tanks. Bare bottom tanks were significantly louder than tanks with a plenum or gravel bottom. In the context of literature documenting effects of noise on hearing, acoustic communication, and stress, the exposure to loud ambient noise may be deleterious to aquarium fishes in several ways; thus, system soundproofing techniques are offered. This project demonstrated the utility of citizen science to gather a data set across a large geographic area on a feasible budget, while providing opportunities for professional aquarists to understand the acoustic environment of their systems and appreciate the utility of research to improve animal management.

Evaluating ontogenetic patterns of habitat use by reef fish in relation to the effectiveness of marine protected areas in West Hawaii

Identifying habitats important to vulnerable life stages of reef fish is an important goal for the effective design and management of Marine Protected Areas (MPAs). However, data on habitat requirements for most fish species are limited. Using a benthic habitat map that characterized reef habitats on the island of Hawaii , we examined ontogenetic patterns of habitat use by each of the life stages of endemic (i.e., Ctenochaetus strigosus; Ctenochaetus hawaiiensis), non-targeted species (i.e., Acanthurus nigrofuscus; Chromis agilis; Thallasoma duperrey; Paracirrhites arcatus) and targeted aquarium fish species (Zebrasoma flavescens; C. strigosus; C. hawaiiensis; Chaetodon multicinctus) in relation to the effectiveness of existing MPAs designed to replenish aquarium fishes targeted by the aquarium trade. Our study empirically demonstrates that many species shift habitats ontogenetically while others remained in the same habitats as they matured. And among those that shifted habitats, depending on species, adults shifted either to more structured (branching coral in mid-depth aggregate and boulder habitats in 5 to 11m depths) or to less structured substrates (shallow turf-rich boulder habitats in 0 to 11m depths). In addition, this study shows how the spatial characteristics of the MPA (i.e., reef size) may be important to reef fish assemblages and ultimately the effectiveness of MPAs to replenish protected ornamental fishes. It is therefore critically important that the management and future design of MPAs provide sufficient diversity and quantities of habitats for all life stages of managed species in order to ensure the replenishment necessary to satisfy their conservation needs and management goals.

Identification of the hybrid between Oryzias latipes and Oryzias curvinotus using nuclear genes and mitochondrial gene region

Commercialized transgenic fish should be sterilized to prevent their genetic effects on native wild fish in the event of their accidental release to the environment. Diploid and allotriploid hybrids between Oryzias latipes and Oryzias curvinotus are sterile, which contributes to the sterilization of transgenic O. latipes or O. curvinotus strains, for example, fluorescent aquarium fish. However, it is very difficult to distinguish these hybrids from their parental species by morphological measurements. Thus, we confirmed whether our previously developed species identification method for O. latipes and O. curvinotus by restriction fragment length polymorphism (RFLP) analysis of polymerase chain reaction (PCR) products of nuclear DNA gene regions, namely, PCR-RFLP using Hinf I or Hsp92 II for the aromatase gene, Rsa I for the calmodulin gene, and Hae III for the caspase-6 gene, is useful for distinguishing the diploid and allotriploid hybrids from their parental Oryzias species. We found that the hybrids have maternal mitochondrial DNA by PCR-RFLP analysis using Mse I of the 16S rRNA gene.

Parvalbumin characteristics in the sonic muscle of a freshwater ornamental grunting toadfish (Allenbatrachus grunniens)

The grunting toadfish, Allenbatrachus grunniens, is an ornamental fish in freshwater aquariums, and it has the ability to produce sounds. The sonic muscle of the toadfish is the fastest vertebrate muscle ever measured, and the rates of Ca(2+) transport and cross-bridge dissociation are also the fastest. Parvalbumins (PAs) are Ca(2+)-binding proteins that help in muscle relaxation in vertebrates. Several PA isoforms have been identified in variable ratios in different muscle types. Both male and female grunting toadfish have intrinsic sonic muscles attached to their swim bladders, but no significant difference in morphology between male and female sonic muscles has been observed. In this study, we used SDS-PAGE and western blotting to characterize the total PA expression and to identify the PAs from the sonic muscle and the white body muscle of A. grunniens. Although the total PA concentrations were similar in sonic and white muscles, there were differences in the isoform percentages. Two and four PA isoforms were identified from sonic muscle and white muscle, respectively. The estimated sizes of PA1, PA2, and PA3 in the sonic muscle of the grunting toadfish were 10, 10.5, and 10.5 kDa, respectively, and the isoelectric points of PA1, PA2, and PA3 in the grunting toadfish were 4.77, 4.58, and 4.42, respectively. In the sonic muscle, the primary PA isoform was PA1, which comprised more than 94 % of total PA, whereas PA2 comprised only 5 % of the total PA content. In contrast, in white muscle, the primary isoform was PA2, which comprised 58 % of the total PA. Both PA1 (with PA1a) and PA3 represented approximately 20 % of the total PA in white muscle. These results indicate that there is no positive correlation between a high PA content and the speed of muscle relaxation; however, PA1 might have the greatest effect on the relaxation of the grunting toadfish's sonic muscle.

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.

Opportunities for Public Aquariums to Increase the Sustainability of the Aquatic Animal Trade

The global aquatic pet trade encompasses a wide diversity of freshwater and marine organisms. While relying on a continual supply of healthy, vibrant aquatic animals, few sustainability initiatives exist within this sector. Public aquariums overlap this industry by acquiring many of the same species through the same sources. End users are also similar, as many aquarium visitors are home aquarists. Here we posit that this overlap with the pet trade gives aquariums significant opportunity to increase the sustainability of the trade in aquarium fishes and invertebrates. Improving the sustainability ethos and practices of the aquatic pet trade can carry a conservation benefit in terms of less waste, and protection of intact functioning ecosystems, at the same time as maintaining its economic and educational benefits and impacts. The relationship would also move forward the goal of public aquariums to advance aquatic conservation in a broad sense. For example, many public aquariums in North America have been instrumental in working with the seafood industry to enact positive change toward increased sustainability. The actions include being good consumers themselves, providing technical knowledge, and providing educational and outreach opportunities. These same opportunities exist for public aquariums to partner with the ornamental fish trade, which will serve to improve business, create new, more ethical and more dependable sources of aquatic animals for public aquariums, and perhaps most important, possibly transform the home aquarium industry from a threat, into a positive force for aquatic conservation.

Tricaine methane-sulfonate (MS-222) application in fish anaesthesia

Summary Tricaine methane-sulfonate (MS-222) is one of the most widely used anaesthetics for poikilotherms worldwide. This paper outlines its anaesthetic efficacy and dosage in fish and legislation for its use, fish stress responses to MS-222 anaesthesia and its effect on fish physiology and blood properties, pharmacokinetics, genotoxicity, immune response, potential interference with fish hepatic cytochrome P450 spectra, and its impact on nerve sensitivity. Key questions arising from the available data are analysed, such as regulatory constraints on its use, the need for the standardization of buffering protocols, and interdependencies of the factors impacting the specific applicative efficacy of MS-222. Current research has provided an abundance of data on MS-222 use in fish, although the applications within these studies are often impractical at the farming level. Specific emphasis is therefore placed on highlighting application strategies on a practical basis, presenting potential future research on topics that require in-depth analysis (preparation and storage of anaesthetic solutions, pre-anaesthetic sedation and stress reduction, cortisol response in aquarium fish, toxicity of MS-222 metabolites, and possible immunodepressive properties). Additionally, both from a scientific and practical perspective, it is necessary to have a better understanding of safety margins, induction, immersion and recovery times for many (marine and freshwater, farmed and ornamental) fish species in order to achieve optimal utilization.

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

BackgroundPoorly 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 FindingsWe 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/SignificanceWe 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.

A general review of parasitic Annelida (Hirudinea) recorded from different habitats and hosts in Turkey

To date, parasitic leech species have not been intensively studied in Turkey, and studies on the leeches of Turkey have concentrated primarily on lakes. According to literature data, a total of 13 parasitic leech species (3 species from marine fish, 8 species from freshwater fish, 1 species from brackish water fish, and 1 species from aquarium fish) have been recorded in different parts of Turkey. Interest in this group has increased during the last 2 decades, but a large part of the Turkish freshwater habitats remains to be studied with regard to the parasitic leech species. In this study, information is given on the distribution of the leech species that have been previously recorded. The collected data show that the freshwater parasitic leech fauna of Turkey is composed of cosmopolitan or widely distributed species.

Aquarium Fish: Study on Mycobacterial Infection

Aquarium Fish: Study on Mycobacterial Infection

Reef fish Breeding and Hatchery Production Using Brackishwater, A Sustainable Technology with Special Reference to Clark’s Clownfish, Amphiprion Clarkii (Bennett, 1830)

The present study on spawning and larval rearing of reef associated clownfish, Amphiprion clarkii was investigated under captive condition. Fishes and sea anemones were obtained from the traders and maintained in a conditioning tank. After pair formation, they laid eggs in the spawning tank, which were sticky, capsule shaped and yellow orange in colour. The eggs were allowed to remain in the same tank till hatching up to eight days for incubation. Spawning, embryonic development, hatching success, larval survival and juvenile production were studied in detail. Optimum water quality parameters were also standardized for the hatchery operations. The size range of newly hatched larvae measured 3.5 to 3.8 mm in length and they were transferred to separate larval rearing tanks. The first white band was prominent on the body between 15 to 17 th day, an indication of metamorphosis. The complete metamorphosis was occurred on 25 th day after hatching. The larvae were initially fed with micro-algae, rotifers, Artemia nauplii and later they accepted frozen Artemia and squashed boiled meat of oysters and clams. The present findings have shown the prospective sign for captive breeding of a highly demanded aquarium fish using brackishwater, by removing the existing foremost technological snag of rearing them in running seawater.

Transcriptomic profiles of Japanese medaka (Oryzias latipes) in response to alkalinity stress

Oryzias latipes (Adrianichthyidae), known as Japanese medaka or Japanese killifish, is a small 2-4 cm long fish common in rice paddies in coastal Southeast Asia and is also a popular aquarium fish. It has been widely used as a research model because of its small size and because it is very easy to rear. Alkalinity stress is considered to be one of the major stressors on fish in saline-alkaline water. As very little is known about molecular genetic responses of aquatic organisms to alkalinity stress, we examined genome-wide gene expression profiles of Japanese medaka in response to carbonate alkalinity stress. Adult fish were exposed to freshwater and high carbonate alkaline water in the laboratory. We designed a microarray containing 26,429 genes for measuring gene expression change in the gills of the fish exposed to high carbonate alkalinity stress. Among these genes, 512 were up-regulated and 501 were down-regulated in the gills. These differentially expressed genes can be divided into gene groups using gene ontology, including biological processes, cellular components and molecular function. These gene groups are related to acid-base and ion regulation, cellular stress response, metabolism, immune response, and reproduction processes. Biological pathways including amino sugar and nucleotide sugar metabolism, porphyrin and chlorophyll metabolism, metabolism of xenobiotics by cytochrome P450, drug metabolism, aminoacyl-tRNA biosynthesis, glycine, serine and threonine metabolism, ascorbate and aldarate metabolism, pentose and glucuronate interconversions, glutathione metabolism, and fructose and mannose metabolism were significantly up-regulated. Alkalinity stress stimulates the energy and ion regulation pathways, and it also slows down the pathways related to the immune system and reproduction.

A novel approach to rapid detection of acute water toxicity and its policy implications for grassroots sustainable environmental monitoring

Unknown chemicals, emerging contaminants, and the resulting reactions among them make early detection and warning of acute water toxicity extremely challenging. The conventional approach using small fish for toxicity monitoring normally requires a designated species of fish and over a week's time to complete, including dilution of the wastewater, a pre-test, and a full test. It often increases chances for error and delays emergency management. This paper reports a novel approach, based on grassroots knowledge and field and lab experience in Jilin, China. This approach uses a combination of different species of aquarium fish to achieve fast and reliable monitoring. It tests the original source water directly without going through the dilution procedure, while paying attention to the time factor. The approach does not require a pre-test and may shorten the time needed for detecting acute toxicity to a few minutes, using a new classification of aquatic toxicity levels. It is inexpensive to use and may be easily adopted by grassroots organizations. The approach is "greener" and more financially and socially sustainable than traditional approaches. The wide use of the approach has the potential to encourage policy innovations for making toxicity monitoring grassroots based and more effective in reducing acute contamination emergencies.

Pattern of Freshwater Fish Diversity, Threats and Issues of Fisheries Management in an Unexplored Tributary of the Ganges Basin, Northern India

The present study was conducted to assess the current freshwater fish biodiversity status of an unexplored river Ghaghara, a major tributary of river Ganga in Uttar Pradesh, India. Altogether, 62 species of fish representing 48 genera and 24 families were described. The various diversity index packages have been used to assess the fish diversity and diversity is also correlated with habitat variables. The Cypriniformes was recorded to be the most predominated order, contributing to 41.8% of fish species followed by Siluriformes (36.4%). The study shows that this river supports considerable percentage of food fish (79.0%), aquarium fish (48.4%), highly priced fishes (33.9%) and also sport fish (9.7%). The threat status as per current IUCN Red List criteria showed that most of the species are under lower risk least concern (LRlc) category, however, Indian assessment shows that about 23% fish species under threatened list (EN= 4, VU=10). Several anthropogenic activities like barrages, waste water dumping, over fishing, sedimentation, change in land use pattern etc. were found responsible to threaten the fish diversity. As the threats to fish biodiversity in the Ghaghara river are slowly becoming serious and conservation of fishes has become urgent, and integrated and sustainable fisheries management plan should therefore be developed.

Assessment of diclofenac LC50 reference values in juvenile and embryonic stages of the zebrafish (Danio rerio)

The aim of the study was to compare the acute toxicity of diclofenac to juvenile and embryonic stages of the zebrafish (Danio rerio). Acute toxicity tests were performed on the aquarium fish Danio rerio, which is one of the model organisms most commonly used in toxicity testing. The tests were performed using a semi-static method according to OECD guideline No. 203 (Fish, acute toxicity test). Embryo toxicity tests were performed in zebrafish embryos (Danio rerio) in compliance with OECD No. 212 methodology (Fish, short-term toxicity test on embryo and sac-fry stages). The results were subjected to a probit analysis using the EKO-TOX 5.2 programme to determine 96hLC50 and 144hLC50 (median lethal concentration, 50% mortality after a 96 h or 144 h interval, respectively) values of diclofenac. The statistical significance of the difference between LC50 values in juvenile and embryonic stages of Danio rerio was tested using the Mann-Whitney non-parametric test implemented in the Unistat 5.1 programme. The LC50 mean value of diclofenac was 166.6 +/- 9.8 mg/L in juvenile Danio rerio, and 6.11 +/- 2.48 mg/L in embryonic stages of Danio rerio. The study demonstrated a statistically higher sensitivity to diclofenac (P < 0.05) in embryonic stages compared to the juvenile fish.

Diet and food consumption of the pearl cichlid Geophagus brasiliensis (Teleostei: Cichlidae): relationships with gender and sexual maturity

Despite the importance of the pearl cichlid Geophagus brasiliensis for the aquarium fish trade worldwide and its wide distribution, many aspects of its biology, such as the relationships between its feeding ecology and reproductive behavior, are not fully understood in natural conditions on its native habitat. In this paper, we investigated its diet focusing on how differences in diet and food consumption are related to differences in gender and sexual maturity. The digestive tract of each individual was dissected and had its content analyzed, whereas each gonad was microscopically analyzed to determine gender (male/female) and sexual maturity (immature/mature). A total of 28 females and 31 males were analyzed. Mature individuals were more common than immature specimens both for males (64.50%) and females (64.30%). The analysis of 52 individuals with non-empty digestive tracts revealed a diet comprised of 27 items. According to the Index of Alimentary importance (%IAi), the most important food items in the diet were Gastropoda (37.30%), fragments of vascular plants (15.16%), detritus (10.14%), Amphipoda (9.24%), and fish scales (6.29%). Mature males had more empty stomachs (65.00%) when compared to immature males (27.27%) and immature (55.56%) and mature females (40.00%). Also, mature females seemed to have more food consumption (greater mean values of total volume) in their digestive tracts than mature males. Some hypotheses are proposed in order to distinguish if this gender-based difference in food consumption in mature individuals of the pearl cichlid could be associated with the development of primary and secondary sexual characteristics or with asymmetrical time invested in parental care activities.

Aggression and Welfare in a Common Aquarium Fish, the Midas Cichlid

Many species of fishes are aggressive when placed in small aquaria. Aggression can negatively affect the welfare of those individuals toward whom it is directed. Animals may behave aggressively in order to defend resources such as food, shelter, mates, and offspring. The decision to defend depends on the distribution of resources and on ecological factors such as number of competitors, amount of available space, and amount of habitat complexity. This study tested the effects of these factors on aggression in a common aquarium fish, the Midas cichlid (Amphilophus citrinellus). The study found that time spent behaving aggressively was not associated with small-scale differences in group size or available space. Aggression was significantly lower in a large aquarium with a complex habitat. Aquaria of sizes typically used in the companion animal (pet) hobby did not provide optimal welfare for cichlids housed with aggressive conspecifics. The public should be aware that this and similar species require larger aquaria with complex habitat, which elicit more natural behavior.

Reproductive biology of Puntius denisonii, an endemic and threatened aquarium fish of the Western Ghats and its implications for conservation

This study presents fundamental information on the reproductive biology of Puntius denisonii, an endemic and threatened aquarium fish of the Western Ghats Hotspot. Results are based on the observations from three river systems, Chandragiri, Valapattannam and Chaliyar. Maximum observed total length in P. denisonii was 162mm and 132mm for males and females, respectively. Males attained sexual maturity at a lower size than females with mean size at first maturity determined as 85.33 plus or minus 1.52 mm for males and 95.66 plus or minus 1.15 mm for females. Puntius denisonii spawned from October to March with minor differences in the peak breeding months between the three river systems, which were studied. Sex ratio deviated significantly from 1:1 and was skewed in favour of males. Absolute fecundity varied from 376 (fish of 102mm total length) to 1098 (fish of 106mm total length) eggs. Currently, the closed seasons for P. denisonii have been put in place during June, July and October based on the (mis)assumption that the species breeds during these three months. However, the results of the present study have helped us to understand more about the reproductive biology of the species so as to recommend more appropriate seasonal closures. The months from October until March need to be designated as a closed season for protecting the breeding population of P. denisonii.

Effect of methyl parathion and chlorpyrifos on certain biomarkers in various tissues of guppy fish, Poecilia reticulata

Tests of acute toxicity were performed on the most common species of aquarium fish, Poecilia reticulata. Guppies ( P. reticulata) were exposed to progressive concentrations of methyl parathion (MP) and chlorpyrifos (CPF); a semi-static method according to guidelines of OECD was used. Tests of acute toxicity were conducted using 10 fish for each separate concentration and for the control group. The results were subjected to probit analysis to determine the 96 h LC 50 values. The 96 h LC 50 values of MP and CPF to P. reticulata were 8.48 ppm/L (5.98–10.89) and 0.176 ppm/L (0.313–0.224) respectively. In addition, behavioral changes at each concentration were observed for the individual fish. Fish were exposed for 96 h to different sublethal concentrations of MP and CPF (¼ LC 50, 1/8 LC 50 and 1/10 LC 50) and their oxidative stress-induction potential was estimated in brain, liver and gills of fish. MDA content is induced in all tissues but maximum rise was observed in gills (161% and 153% for MP and CPF respectively). With regard to antioxidant defense system (ADS), GSH level decreased in the brain, liver and gills of tissues of MP treated fishes (22%, 6% and 13% respectively) and showed increase in brain and gills CPF treated (23% and 21% respectively). CAT, GST, GR and SOD levels fluctuated in all treatment groups relative to the control. Brain AChE showed dose-dependent inhibition in fish exposed to the higher concentrations reached 45% and 66% for MP and CPF respectively. Collective findings demonstrated that pesticide exposure of fish induced an increase in MDA and fluctuated ADS along with inhibited AChE. These findings may be used as valuable biomarkers for evaluation of water pollution.