Koi Carp Research Articles

Exploring the Genetic and Morphological Diversity of Argulus Ectoparasite Infecting the Aquaculture and Ornamental Fish in Tripura

Background: The present study screened for isolation of Argulus spp. infecting fishes based on the report of causing substantial economic losses both in aquaculture ponds and ornamental shops across several locations in Tripura, India. Methods: Identification of Argulus spp. was performed based on morphological, and molecular techniques. The molecular identification of Argulus spp. was performed using universal eukaryotic 18S rRNA genetic markers. Prevalence analysis was performed to determine the infestation rate of Argulus spp. in different hosts. Result: Seven A. japonicus, one A. coregoni and one A. foliaceus isolates were identified based on molecular and morphological features. In the present study it was found that A. japonicus infected a wide range of host species, including Goldfish, Milky Koi carp, Mrigal, Rohu, Catla and Subunkin. It was the first instance of A. japonicus infecting milky koi carp both in India and globally. On the other hand, A. foliaceus and A. coregoni infected only tiger oscar and goldfish respectively, indicating a rather narrow range of host diversity.

Evaluation of nutrient composition of selected small indigenous fish species in Bangladesh and potential contribution to nutrient intakes

Small indigenous fish (SIF) are recognized as easily available, and abundant source of macronutrients and micronutrients in Bangladesh. The current investigation was undertaken to assess the existing heavy metal, mineral, vitamin, and others nutrient content of small indigenous freshwater fish in Bangladesh. Eight indigenous fish (Mola, Tengra, Baim, Punti, Chanda, Guchi, Koi, and Taki) were selected for this study. The AAS (Atomic Absorption Spectrophotometer), ICP-MS (Inductively Coupled Plasma-Mass Spectrometry), and the Association of Official Analytical Chemists methods outlined were used to determine the proximate compositional analysis of fish. The highest fat content was found in koi fish. Protein was highest in both baim and taki fish. Iron, zinc, vitamin A, and vitamin B12 content were highest in mola fish. Highest calcium and phosphorus were found in the chanda and taki fish. The study concludes that small indigenous fish are valuable sources of fat, protein, ash, iron, zinc, calcium, phosphorus, potassium, vitamin A, and vitamin B12, which are important for maintaining good health. Our findings suggest that small indigenous fish could serve as a viable option for addressing the nutritional needs for the children (6–23 m age), and Pregnant and lactating women in Bangladesh as a tool to fight malnutrition.

Molecular Fish Sexing on Taisho Sanshoku Koi (Cyprinus carpio) Based on ArS.9-15 Gene Amplification using PCR Method

Taisho Sanshoku is a variant of Koi fish (Cyprinus carpio) that has high demand due to its high economic value and relatively expensive price. This study aimed to determine the sex of the Taisho Sanshoku Koi fish by molecular sexing using the PCR method to amplify the ArS.9-15 gene. This study was initiated by rearing a 4–6 month-old of 10 Taisho Sanshoku Koi fish in a fish tank with a filter and oxygen aeration. The fish were fed with fish pellets for 1–3 days. The Koi fishes were then anesthetized using Koi anesthesia containing β-hydroxyethyl phenyl ether. Each fish's peripheral blood was collected as much as 0.5 mL per fish and then stored in tubes containing Ca-EDTA anticoagulant. The genomic DNA was extracted from peripheral blood samples and used as a template DNA for PCR amplification targeting ArS.9-15 gene. Agarose with 1.5% concentration and CybrSafe staining was used in electrophoresis for visualization of the PCR results then visualized in a dark chamber using a UV transilluminator. The Taisho Sanshoku Koi fish's sex was determined using descriptive analysis based on the electrophoresis results. According to the PCR results, the female Taisho Sanshoku Koi fish only produced one 800 bp DNA band, whereas the male fish produced two 800 bp and 1,100 bp DNA bands. The outcome of molecular fish sexing of the 10 Taisho Sanshoku Koi fish reported that 60% were male and 40% were female.

Protective Role of Sulforaphane against Physiological Toxicity of Triphenyltin in Common Carp (Cyprinus carpio haematopterus).

This experiment mainly explored the protective role of sulforaphane (SFN) against physiological toxicity of triphenyltin (TPT) in Cyprinus carpio haematopterus. In total, 320 Fish (56.90 ± 0.40 g) were randomly divided into four groups with four replicates each. The control group was fed the basal diet, the TPT group (TPT) was exposed to 10 ng L-1 TPT on the basis of the control group, the SFN + TPT group (TPT + SFN) was fed a diet supplemented with 10 mg kg-1 SFN on the TPT group, and the SFN group (SFN) was fed a diet supplemented with 10 mg kg-1 SFN. After 56 days of breeding trials, the results showed that TPT exposure resulted in a remarkable decrease (p < 0.05) in final weight, weight gain rate (WGR), specific growth rate (SGR), and condition factor (CF), but an increase (p < 0.05) in feed conversion ratio (FCR) and hepatosomatic index (HSI) of fish. TPT treatment decreased (p < 0.05) the amounts of hematocrit (Hct) and hemoglobin (Hb), plasma complement component 3 (C3) and C4 contents, alternative complement pathway (ACH50), acid phosphatase (ACP) and lysozyme (LZM) activities, liver glutathione (GSH) content, catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPX) activities, interleukin 10 (IL-10), and SOD mRNA expressions, but increased (p < 0.05) plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities, liver malonaldehyde (MDA) content, tumor Cyclooxygenase 2 (COX2), and necrosis factor α (TNFα), IL-1β, and MDA mRNA expressions. A histological analysis of the liver showed that a higher occurrence rates of the hepatocyte hypertrophy, nuclear disappearance and hepatocyte vacuolization was observed in the hepatocytes of fish exposed to TPT, and it was accompanied by the dilation of hepatic sinusoids. In addition, the toxicity induced by TPT was significantly improved in the groups that were treated with SFN, and SFN was able to improve growth performance and immunity, alleviate TPT-induced changes in inflammatory factors, ameliorate oxidative stress, and increase the activity of antioxidant enzymes (p < 0.05). The addition of SFN also alleviated liver damage caused by TPT and protected the structural integrity of the liver. Overall, these findings suggest that TPT inhibited the growth, immunity, and antioxidant capacity of Cyprinus carpio haematopteru. Dietary SFN could be beneficial for growth promotion, immunity, antioxidant capacity, and protection of liver structural integrity. Therefore, SFN is a prospective feed supplement for ameliorating the damage caused to fish by TPT contamination.

Propagation of koi herpesvirus using embryonated chicken eggs: a potential substitute method for fish vaccine production?

Koi herpesvirus disease (KHVD) is caused by a large DNA virus that commonly infects carp, Cyprinus carpio (koi and common carp). KHVD has spread rapidly across the globe and caused high mortality in all ages of common carp and koi. Until now, no effective treatment has been applied to prevent KHV infection impacting the mass production of koi and common carp . An environmentally friendly alternative strategy for controlling fish disease is vaccination. One of the challenges facing conventional viral vaccine production is the requirement for koi or common carp cell cultures, which must be frequently maintained with expensive materials required for virus propagation. This study aims to obtain KHV that has been propagated in embryonated chicken eggs (ECE) to formulate an affordable KHV vaccine for the aquaculture industry. This research consisted of three stages; the first stage was virus inoculation into various parts of eggs (allantoic fluid, chorioallantoic membrane, amniotic fluid, and egg yolk). The second stage was observing viral growth and collecting ECE fluid and membranes. The third stage involved quantitatively determining the viral genomic copy numbers using the quantitative Polymerase Chain Reaction (qPCR) assay. KHV propagation in various parts of ECE resulted in varying viral genomic copy numbers with a high DNA copy number reported in allantoic fluid on the third day after inoculation. Further work is required to monitor virus titer in later passages and optimize methodology for using ECE as the potential alternative to cultured cells as the medium for virus propagation. In the future the system could be developed to produce promising vaccine candidates with more affordable vaccine prices for the Indonesian fish farming industry.

PEMELIHARAAN IKAN KOI (CYPRINUS CARPIO) PADA KOLAM BETON

Koi (Cyprinus carpio) is a type of fish that belongs to a strain of common carp (Cyprinus carpio). Koi fans in Indonesia not only keep koi fish in ponds, but also take part in koi contests so that they can increase the prestige of their owners. Koi fish is a freshwater ornamental fish commodity that has economic potential in national and international markets. This research aims to determine the performance of koi fish cultivation in concrete ponds. This research activity was carried out in January-February 2024 at the Lingsar Fish Seed Center (BBI), West Lombok, West Nusa Tenggara. The data collection techniques used in this research are descriptive methods and field observations. The results obtained are koi fish cultivation activities including pond preparation, selection and distribution of seeds, the grow-out process where the grow-out process includes feed management, water quality management and koi fish health management. Next, growth observations were carried out where growth for 21 days could provide significant results, which can be seen from the absolute weight and length obtained, namely 2.3 grams and a length of 3.28 cm. Then the FCR value obtained was 0.53 and SR 99.6%. Meanwhile, for optimal maintenance water quality, the maintenance temperature range is around 26-30°C and the pH is around 6.5-8.0. From these data it can be said that the koi fish cultivation has been successful

Analisa Usaha Budidaya Ikan Koi (Cyprinus rubrofuscus) pada Sistem Vertiqua Menggunakan Filter Biofikal Atas

The background of this research is that vertiqua is considered to have high production costs and small profits. Therefore, a business analysis is needed to increase the effectiveness of the fish farming business using the vertiqua system. The purpose of this study is to analyze the aquaculture business using the vertiqua system including capital and profit obtained. This research uses qualitative methods with descriptive explanations. The results of the research that has been done show that the R / C Ratio value obtained is 1.66, meaning that every 1 cycle cost expenditure will get 1.66 revenue. Koi fish farming using the vertiqua system is said to be feasible to continue because the R / C Ratio value is 1. The JWPM value with the calculation of 8 cycles for 1 year is 1.4, meaning that it takes 2 months and 2 days for the capital to return. Based on the business analysis conducted, the production of koi fish seeds using the upper biofical filter vertiqua system can be said to be feasible and has the potential to be further developed, because it can provide good profits with a good JWPM. In addition, cultivation using the upper biofical filter vertiqua system is very efficient in providing care for koi fish cultivation.

Struktur Komunitas Fitoplankton pada Budidaya Ikan Koi (Cyprinus Rubrosfuscus) dalam Sistem Vertiqua Menggunakan Biofikal Filter Atas

Vertiqua biofical top filter is a cultivation technique with a recirculation system that utilizes limited land. Vertiqua is a solution for cultivation. When cultivating koi fish in vertiqua, the feed capacity increases and there is a high nutrient load so that the waters are easily polluted, therefore the presence of an upper biophysical filter can reduce pollution. This is important to study, especially the structure of the phytoplankton community because it is one of the biological indicators of ponds in koi fish cultivation. This research was carried out for 6 weeks in Sindangpalay Ciberem Sukabumi. The research was carried out by taking phytoplankton in the vertiqua at intervals of once every 2 weeks. The data analysis in this research is abundance, diversity, uniformity and dominance. During the research results obtained were abundance 636-673, diversity 2.6, uniformity 0.9, and dominance 0.01. The water quality studied was ammonia, nitrate, nitrite, phosphate, pH, DO, turbidity and temperature. These waters are stable and healthy, which is a positive indicator to support fish farming activities. The water quality in Vertiqua is classified as good and the ecosystem is balanced, these waters are ideal for supporting the productivity and health of farmed fish.

Histopathological Changes in The Gills of Cyprinus Carpio Infested With Ectoparasites

Abstract This study aims to determine the histopathological changes in koi fish gills based on the degree of ectoparasitic infestation. The study found several categories of ectoparasite infestation, namely normal, mild, moderate, heavy and very heavy. In the gills with mild category, there were histopathological changes in hyperplasia, in the gills with moderate infestation category, hyperplasia and fusion occurred, in the heavy category infestation there were hyperplasia and telangiectasia, and in the category of very heavy infestation, there were hyperplasia. fusion, telangiectasia and vacuoles. The histopathological scoring value on the gills with the categories of mild, moderate, severe infestation degrees is the mild category, while the gills with the category of very heavy infestation degrees is the heavy category. Correlation test of the degree of infestation and scoring of histopathological changes obtained a ρ value of 0.832. It can be concluded that the increase of ectoparasite infestetation will be followed by the increase of tissue damage level.

The influence of different stocking density on growth rate and survival rate koi larvae (Cyprinus carpio)

Abstract Stocking density has an important role in the survival and growth of fish larvae. The purpose of this study was to determine the optimal stocking density level for larval rearing with improved feed. Tubifex sp. which has a high protein content of about 57% and fat as much as 13%. The method used was the experimental method with a completely randomized design (CRD) on 4 different treatments of stocking density with 3 replications. The treatments given were P0/Control (1 individual/L), P1 (2 individuals/L), P2 (3 individuals/L), and P3 (4 individuals/L) maintained for 49 days. The results obtained during the study were the growth rate values of P0 (0.021 gram/day), P1 (0.017 gram/day), P2 (0.016 gram/day), and P3 (0.017 gram/day). The survival rates are P0 (90.00%), P1 (91.00%), P2 (90.33%), and P3 (87.50%). Absolute length values P0 (1.94cm ), P1 (1.70cm ), P2 (1.70cm), and P3 (1.77 cm) The quality of the water obtained is that the temperature ranges from 26–29, the pH is 6.8–8.1, and the DO is 5–6. The results showed that different stocking densities had no significant effect (p &gt; 0.05) on the survival and growth rate of koi fish.

Maternal Immunity and Immune Improvement of Koi Cyprinus rubrofuscus Larvae after DNA Vaccine against Hoi Herpesvirus

Vaccination is an efficient step in preventing disease caused by koi herpesvirus in koi fish (Cyprinus rubrofuscus). This study aimed to investigates the impact of maternal broodstock vaccination with ORF81 DNA vaccine on the transmission of maternal immunity to offspring against KHV. The ORF81 DNA vaccine has been shown to increase RPS, but its effect on maternal immunity in koi offspring after vaccination has not been evaluated. The study examined koi broodstocks vaccinated with the ORF81 DNA vaccine 45 and 60 days before spawning (45V and 60V) at a dose of 12.5 μg/100 g. Immunological parameters were assessed in broodstock, eggs, and larvae. Immune gene expression was also analyzed using the qPCR method. The results showed that lysozyme activity and antibody levels in eggs from vaccinated mothers were higher, though not significantly different. Meanwhile, lysozyme activity and antibody levels in mothers were significantly higher (p&lt;0.05) compared to controls. Immunoglobulin-M gene (IgM) and recombination-activating gene 1 (RAG1), were significantly induced. The relative survival percentage increased significantly in larvae produced from broodstocks with 60V. These findings indicate that broodstocks treated with the ORF81 DNA vaccine can enhance the immune response of their offspring.

Fecal microbiota transplantation accelerates restoration of florfenicol-disturbed intestinal microbiota in a fish model

Antibiotic-induced dysbiosis in the fish gut causes significant adverse effects. We use fecal microbiota transplantation (FMT) to accelerate the restoration of florfenicol-perturbed intestinal microbiota in koi carp, identifying key bacterial populations and metabolites involved in the recovery process through microbiome and metabolome analyses. We demonstrate that florfenicol disrupts intestinal microbiota, reducing beneficial genera such as Lactobacillus, Bifidobacterium, Bacteroides, Romboutsia, and Faecalibacterium, and causing mucosal injuries. Key metabolites, including aromatic amino acids and glutathione-related compounds, are diminished. We show that FMT effectively restores microbial populations, repairs intestinal damage, and normalizes critical metabolites, while natural recovery is less effective. Spearman correlation analyses reveal strong associations between the identified bacterial genera and the levels of aromatic amino acids and glutathione-related metabolites. This study underscores the potential of FMT to counteract antibiotic-induced dysbiosis and maintain fish intestinal health. The restored microbiota and normalized metabolites provide a basis for developing personalized probiotic therapies for fish.

Effect of Synthetic Hormone on Breeding Potential of Gold Fish (Carassius auratus)

The acquisition of ornamental fish is becoming a prerequisite for luxury. Fish which are ornamental are getting progressively more popular as a way to alleviate stress. Among these, goldfish and koi carp are the most prevalent visually appealing fish that happen to be consistently in demand by fish hobbyists. For millennia, the method of raising these fish has been standardized. One of the most significant advancements in the aquaculture of ornamental fish that are vital to economic prosperity is artificial propagation. Induced breeding is a straightforward approach that guarantees a timely supply of seed spawn for fish culture. The aim of the current study was to use ovaprim™ hormone at various dosages to encourage breeding in gold fish (Carassius auratus auratus) kept in captivity. Every breeding pair, including the control, was bred. There were significant (&lt;0.05) variations in the success of fertilization and hatching rate at various doses between treatments and the control group. Ovaprim™ at a dose of 0.7ml/kg and 1.4ml/Kg was found to be effective for male and female respectively with 54% fertilization rate, 43 % hatching rate. The positive response to synthetic hormone (ovaprim™) with considerable fertilization and hatching rate makes it possible to conduct the breeding program of this species commercially and the method can be applicable for commercial culture.

Application of metoclopramide as gastroprokinetic in koi carp (Cyprinus carpio) with positive buoyancy disorders

Application of metoclopramide as gastroprokinetic in koi carp (Cyprinus carpio) with positive buoyancy disorders

Exploring Arthropods as Sustainable Protein Source and the Effect of Cockroach Meal Supplemented Diet on the Growth of Fish

This comprehensive study centres on exploring the arthropods as sustainable protein sources, addressing both human dietary needs and livestock feed requirements. A diverse set of twenty arthropod species were collected from different locations of Kanyakumari District and the species were identified based on the identification keys pertaining to morphological characters. The surveyed animals comprises of Insects: Dragon Fly (Pantala sp.), Western subterranean termite (Reticulitermes sp.), Longhorn beetle (Callipogon sp.), Asiatic rhinoceros beetle (Oryctes rhinoceros), Brown grasshopper (Melanoplus sp.), Bush cricket (Tettigonia sp.), Grasshopper (Diabolocatantops sp.), Housefly (Musca domestica), Cockroach (Periplaneta americana), Termite (Macrotermes sp.), Black carpenter ant (Camponotus sp.), Red carpenter ant (Camponotus sp.); Crabs: Mottled light footed crab (Grapsus albolineatus), Sartoriana sp., Asian paddle crab (Charybdis sp.,),Box crab (Calappa sp.,), Asian shore crab (Hemigrapsus sp.); Millipedes: Yellow spotted millipede (Harpaphe haydeniana), Pill millipede (Arthrosphaera disticta) and African giant millipede (Thyropygus descriptus) were analyzed for the protein content. The samples were tested for protein using Biuret’s method. Among the different arthropods tested insects- Callipogon sp. and Periplaneta americana, crabs - Calappa sp. and Charybdis sp. and Myriapod - Harpaphe haydeniana, exhibited the highest protein content. Crustaceans demonstrated the highest protein content when compared to insects and millipedes. However, since cockroaches are generally considered as a pest and repugnant in human dwelling, it would be ideal to convert cockroach as a sustainable protein source in aquaculture. Moreover. since cockroach showed a higher protein content of 6.146 2.024 mg/ml it was tried as a supplement feed for fish. Cockroach meal was prepared in two different proportions (2% and 3%) to evaluate its impact on the growth of Koi carp fish in comparison with cockroach free meal as control. The inclusion of 3% cockroach powder in the fish meal augmented the growth of Koi carp when compared to the control during a fifteen-day study period. Thus, this study has tapped a potential protein source from insects. Cockroach can be used as an ideal fish feed as it contributes to the pursuit of sustainable and environmentally friendly animal feed source.

Utilization of Indigofera zollingeriana leaves meal in feed formulation to color brightness and growth in koi fish (Cyprinus carpio)

This study aims to determine the effect of the addition of Indigofera zollingeriana in feed formulations with different doses on the color brightness of koi fish. The research design was Completely Randomized Design (CRD) with five treatments and three replications. Treatment P0 was control (without the use of Indigofera leaf meal), P1 was the addition of 5% indigofera meal, P2 was the addition of 10% indigofera meal, P3 was the addition of 15% indigofera meal, and P4 was the addition of 20% indigofera meal. Fingerlings measuring 6 ± 1 cm with a stocking density of 1 fish for 2 L were reared for 30 days in this study. The results showed that P2 with a percentage of 10% Indigofera zollingeriana meal was the best treatment for the brightness of koi fish color (27.23). Still, they had no significant effect on the growth of absolute length (1.04 cm) and absolute weight (1.05 g), feed efficiency (23.08%), and survival rate (100%). The water quality obtained during maintenance was temperature 26-27oC, pH 6.1-7.2, dissolved oxygen 5.2-6.3 mg/L, and ammonia 0.02-0.036 mg/L.Keywords: Fish Color Brightness; Indigofera zollingeriana; Koi Fish

A comprehensive review of current practices, challenges, and future perspectives in Koi fish (Cyprinus carpio var. koi) cultivation.

The Koi fish (Cyprinus carpio var. koi) is an ornamental fish with a high selling value because of its attractive colors, color patterns, body shape, and swimming motion. Koi fish is extensively traded in the international fish market because of their popularity among hobbyists from numerous countries worldwide. This review discusses various aspects of Koi fish cultivation, including genetic involvement, selective breeding strategies, and management systems. By examining crucial factors such as water parameters, technological innovations, and evolving cultivation methods, this review explored their influence on the quality of Koi fish. Breakthrough technologies, such as ornamental fish warehousing and recirculation aquaculture systems, enhance breeding efficiency and profitability. Molecular sexing, feed optimization, and color enhancement strategies are central to pursuing superior Koi fish. Reproduction management, disease prevention, and risk reduction during transport underscore ongoing efforts to ensure their survival. Despite notable progress, several challenges remain, including limited genetic studies, gaps in disease research, and unexplored herbal alternatives. The active involvement of hobbyists and breeders in research initiatives is a pivotal force in unlocking the untapped potential. The holistic approaches to enhance production efficiency and improve care standards require further exploration, paving the way for a sustainable future in the evolving management of Koi fish cultivation.

Echocardiographic evaluation in koi carp (Cyprinus carpio) under manual restraint compared to anesthesia with isoeugenol.

To establish an echocardiographic technique in koi carp (Cyprinus carpio), compare cardiopulmonary parameters under manual restraint versus anesthesia, and provide a gross anatomical and histologic cardiac description. A randomized, crossover echocardiography study was performed in 40 clinically healthy adult, unknown sex, privately owned koi carp on May 10 and 11 through June 26 and 27, 2021. Echocardiography was examined for each koi under manual restraint and isoeugenol at 50 ppm, with 3 measurements per examination performed by a radiologist and cardiologist. Two koi were euthanized for gross anatomic and histologic cardiac evaluation. Mean ejection fraction (EF), stroke volume (SV), and cardiac output (CO) were significantly lower, mean heart rate (HR) was significantly higher, and opercular rate (OPR) was decreased significantly in anesthetized compared to manually restrained koi. Poor reproducibility for EF and SV was observed. Echocardiography was feasible in both manually restrained and anesthetized koi; however, this technique may best be applied to monitoring trends over time in individual fish due to low reproducibility. Significant differences in multiple cardiopulmonary parameters, including HR, EF, SV, CO, and OPR, were present between manually restrained and anesthetized koi. A gross anatomic and histologic cardiac description is provided for this species to pair with the echocardiographic images. This study provides the first description of echocardiography, cardiac gross anatomy, and histology in koi. The results support echocardiography as a safe and practical noninvasive diagnostic for cardiac assessment in koi under both manual restraint and anesthesia.

Teknik Pemeriksaan Parasit Myxobolus sp. pada Ikan Hias Air Tawar di Balai Karantina Ikan Pengendalian Mutu dan Keamanan Hasil Perikanan Surabaya I

The increase in ornamental fish farming in Indonesia has increased significantly during the 2017-2019 period. This improvement process is certainly faced with various challenges such as disease, which is caused by ectoparasites, one of which is Myxobolus sp. This parasite can infect the skin and gills of fish, causing significant financial losses. This study aims to determine the prevalence and intensity of Myxobolus sp parasites in freshwater ornamental fish at the Surabaya I Fish Quarantine Center for Quality Control and Safety of Fishery Products (BKIPM), which was conducted on June 19 - August 18, 2023. The tools and materials used include fish samples, distilled water, 70% alcohol, giemsa dye, swallow and tissue, tray, binocular microscope, computer, dissecting set, object glass, cover glass, dropper pipette, ruler, gloves, beaker glass, workbook, method, and stationery. Native and staining methods were used to examine parasites, while prevalence and intensity were calculated using Kabata's (1985) formula. The results showed that comet fish and koi fish were infected with Myxobolus sp in their gills. The intensity of Myxobolus sp infection in koi fish was classified as severe, while in comet fish it was classified as very severe. The prevalence of Myxobolus sp parasites found in koi fish was 2.32% and in comet fish was 4.20%, both categorized as moderate infection.

Antimicrobial and anthelmintic effects of copper nanoparticles against Koi carp parasites and their toxicity.

This study investigated the invitro antimicrobial and anthelmintic effect of copper nanoparticles (CuNPs) against the bacterium Aeromonas hydrophila, the monogeneans Dactylogyrus minutus, Dactylogyrus extensus, Gyrodactylus cyprini, and the cestode Schyzocotyle acheilognathi, as well as their toxicity to Cyprinus carpio Koi. In the antimicrobial invitro test, the inhibition zone method and minimum inhibitory concentration (MIC) were performed. In order to determine the time and efficacy of monogenean parasite mortality, the parasites were exposed to CuNP concentrations of 20, 50, 100, 150, 200, and 300 mg L-1, and a control group with tank water and one with copper sulphate pentahydrate (CuSO4.5H2O) at a concentration of 0.3 mg L-1, performed in triplicate. The parasites were observed every 10 min for 300 min, and mortality was recorded. For the cestodes, parasites were immersed in CuNP concentrations of 50, 100, 150, and 300 mg L-1. At the end of the invitro tests, the anthelmintic efficacy of each treatment was calculated. To assess the tolerance and toxicity in fish, they were exposed to CuNP concentrations of 0.6, 1.25, 2.5, 5, 10, 20, and 50 mg L-1 for 12 h. The MIC demonstrated that CuNPs effectively inhibited the growth of A. hydrophila up to a dilution of 12,500 mg L-1 and showed an inhibition zone of 14.0 ± 1.6 mm for CuNPs. The results of anthelmintic activity showed a dose-dependent effect of concentration for both groups of parasites, with the most effective concentration being 300 mg L-1 in 120 min. In the toxicity test, the carps showed tolerance to lower concentrations. The study indicated that CuNPs were effective against the studied pathogens. However, it proved to be toxic to fish at high concentrations. The use of low concentrations is recommended still requires further investigation.