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COVID-19 pandemic, caused by the SARS-CoV-2 virus, has adversely impacted every activity and all the sectors including aquaculture globally. Thousands of families of coastal West Bengal are directly or indirectly involved in shrimp farming for their employment and earn handsome income to sustain their lives and livelihoods. A survey was conducted among the stakeholders of the shrimp farming sector to assess the prospective effect of lockdown in all the parts of the shrimp aquaculture sector during both the summer crop and winter crop cultivation. As the strict lockdown norms were implemented during the summer crop so, the severe constraints during this culture were assessed in two phases (Phase I- 21st March to 30th April 2020 & Phase II- 1st May to 21st June 2020) using Garrett's Ranking Analysis and the constraints were ranked accordingly. The constraint of 'uncertainty over the culture and market' ranked 1st and the 'lack of quality seeds' ranked 1st in the 1st and 2nd phase of culture respectively. The uncertainty in the procurement of farming inputs, unavailability of specific pathogen-free (SPF) broodstocks & high health (HH) shrimp seeds, increased cost towards the cultivation, lack of manpower, absence of an assured international market, etc. have halted the shrimp farming operations noticeably. The farm input suppliers have also experienced supply chain disruptions due to lockdown. The Government of India permitted input supply and services in fisheries and aquaculture as an essential service to lessen the pandemic impact. Short-term policy measures are recommended for mitigation measures.

The influence of fluctuating water temperature and dietary oxytetracycline (OTC) at 0 (0X), 80 (1X), 240 (3X), 400 (5X) and 800 mg (10X)/kg biomass/day for 30 consecutive days on the safety of monosex (all male) Nile tilapia Oreochromis niloticus fries in terms of feeding, growth, survival and histopathology of vital organs were assessed. A dose-dependent decline in feed intake and biomass was recorded. The OTC-dosed groups recorded higher mortalities than the control. The therapeutic OTC-dosing (1X) in conjunction with low temperature caused 75.56 ± 8.01% mortality and 25.75% reduced feed intake in 30 days. The mortalities increased with increasing OTC-doses from 85.19 ± 3.39% (1X) to 95.56 ± 2.22% (10X) and fluctuating temperature (12.00-21.50°C) even after the withdrawal of OTC. Relatively mild to moderate histopathological lesions were observed in the kidney, liver and intestine of OTC-dosed fries. These results suggested that dietary OTC and low water temperature may cause adverse effects on monosex O. niloticus fries.

Oreochromis niloticus is imperative in Indian aquaculture attributing to a significant portion of culture fisheries after carps. This study assessed the serum biochemical, haematological, and histopathological changes in O. niloticus juveniles upon dietary administration of florfenicol (FFC) at 15 mg/kg biomass/day (1X) and 45 mg/kg biomass/day (3X) for 10 consecutive days and compared with control. Behavioural changes, feed consumption, survival, and biomass were evaluated. Besides, the levels of serum glucose, calcium, chloride, creatinine, alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase, and blood cell morphology were determined at scheduled intervals. The 10 days of oral dosing resulted in 100% (1X) and 96.15% (3X) survival, reduced feed intake, and biomass. Significant erythrocyte morphological alterations were observed in the 1X group compared to the control. Alterations in haematological parameters of FFC-dosed fish suggested apparent cytotoxicity. A substantial hike in lymphocyte counts and mean corpuscular volume was observed. All the serum biomarkers of O. niloticus increased significantly on day 10 dosing in a dose-dependent manner, except for calcium and chloride, which reduced significantly. Marked histopathological changes like degeneration of renal tubular epithelium and widened lumen in the kidney, and glycogen-type vacuolation, cytoplasmic degeneration, and cytoplasmic vacuolation in the liver were observed during the dosing period. Within 3 weeks of suspension of dosing, the 1X group serum biomarker levels became normal except for alkaline phosphatase. The recovery of serum biomarker levels, haematological values, histopathological and erythrocyte morphological changes suggested that the FFC-induced changes are reversible at the therapeutic dose and are safe for O. niloticus.

To develop vaccine for rohu (Labeo rohita), efficacy of three antigenic preparations from Aeromonas hydrophila were evaluated. Thirty six tanks with ten rohu were divided in quadruplicates (R1 to R4) with nine tanks (G1 to G9). Rohu of G1 to G6 tanks were given intraperitoneal vaccine with outer membrane protein, somatic protein and formalin-inactivated whole cell itself and along with Incomplete Freund’s Adjuvant @ 200 µg/fish, G7 and G8 tanks were injected with Incomplete Freund’s Adjuvant (100 µl/fish) and normal saline (100 µl/fish) respectively and G9 tanks were kept as control. After 28 d, rohu of R3 and R4 were subjected to intramuscular A. hydrophila challenge (LD50) @ 2.85×106 cells/fish for 7 d and RPS (%) was calculated. Specific cellular and humoral immune responses were determined for rohu of R1 and R2. Results showed that rohu immunized with outer membrane protein along with adjuvant could offer an appropriate vaccine strategy.

Immunomodulation is one of the useful tools to prevent diseases in aquaculture. In this study, the immunomodulatory effects of vitamin-E (100 mg/kg feed) and commercial probiotic consortia, Rhodomax™ (5 g/kg feed) on the innate immunity of

The study was conducted to evaluate the vaccination effects on rohu, Labeo rohita head kidney tissues while assessing the vaccine efficacy of Aeromonas hydrophila antigens. Six acclimatized rohu groups were immunized with three antigenic formulations (outer membrane proteins, somatic and whole-cell antigen) @ 200 µg/fish and also with equal volume of Freund's incomplete adjuvant (FIA), separately. Simultaneously, two non-vaccinated groups, i.e., injected with FIA (100µl), normal saline solutions (0.85%) and one control without injection were maintained for 28 days. All rohu were challenged with median lethal dose of A. hydrophila (2.85 × 106 cells/rohu) intraperitoneally. After 7 days, highest cumulative mortality (%) of ˃88% was found for all non-vaccinated groups. During histopathological observations in head kidney tissues of all treatment and control groups, numerous histopathological changes in the nephritic cells like mild loss of typical tubular epithelial lining, necrosis, thickening of renal epithelial lining, haemorrhages, inflammation, distorted and widening of the lumen with vacuolated surrounding and the constricted lumen of nephritic tubules were noticed for vaccinated rohu in contrast to non vaccinated groups before A. hydrophila challenge. In case of all non-vaccinated fish, including control, extensive degenerated and necrotized head kidney tissues were observed, whereas it was least observed in vaccinated rohu after 7 days A. hydrophila challenge. Results suggest that OMPs antigen along with FIA was the premier vaccine approach for improving resistance to Aeromonas disease and reduce mortality in rohu. Similarly, vaccination with all three antigenic formulations, preferably when applied along with FIA, can effectively protect the head kidney against A. hydrophila infection.

The present study reports the first isolation of Chryseobacterium sp. and co-infection with Aeromonas hydrophila in pacu, Piaractus brachypomus fries cultured in West Bengal, India. The infected pacu fries showed white patches on gill, tail rot, skin discoloration, scale loss, skin peeling, emaciation, and kidney inflammation. The yellow pigmented colony from the kidney of pacu on selective cytophaga agar was identified as Chryseobacterium sp. based on colony pigmentation, cell morphology, phenotypic characterization, and 16S rDNA gene sequencing. Phylogenetically, the members of the genus Chryseobacterium clustered together as a separate clade and the strain PLI2 (NCBI accession number KP898212) branched with a non-type strain C. indologenes VIT-CMJ1 (accession number KJ437473 ) with high node value (100). Yet, the strain PLI2 was distinctly different from closely related type strain C. indologenes LMG 8337 (accession number LN681561) with 97% DNA homology and low (80) node value or other type strains of NCBI GenBank database. The challenge experiments indicated that Chryseobacterium sp. PLI2 can cause substantial mortalities (25%) in abraded and bath (2.2 × 107/mL) treated pacu fries. The kidney of challenged pacu became pale and inflamed. Most likely, this report is a new record on the isolation of Chryseobacterium sp. from the kidney of P. brachypomus. Statement of relevance • Co-infection of Chryseobacterium sp. and A. hydrophila in Piaractus brachypomus caused nephropathy and large scale mortalities. • The record of a new bacterial disease Chryseobacterium sp. infection in Indian aquaculture is a serious cause for concern.

The study was carried out to find the prevalence of ectoparasites in carp species specifically Indian Major Carps (IMC) during the post monsoon season (November’16 to March’17). Four groups of ectoparasites viz. myxozoan, ciliophoran, monogenean and crustacean were recorded from a total 500 number of carp species like, Labeo rohita, Catla catla, Cirrhinus mrigala and Labeo calbasu collected from different ponds of selected blocks of South 24-Parganas district of West Bengal. The highest prevalence (64.8%) of infestation had been recorded by Myxozoans and the lowest was by Monogeneans (4.8%). The highest and lowest ectoparasitic prevalence in carp was observed in L. rohita (32.9%) and C. catla (27.3%). Beside these, lower temperature (Average 19.3oC), low pH (Average 6.9) and marginal level of dissolved oxygen (Average 6.0ppm) were also created an unfavorable condition for parasitic infestation during this season. At the end of this experiment it was concluded that disease occurrences due to ectoparasites was high in winter with some key factors like temperature, pH and dissolved oxygen (DO).

The present study attempted sequencing the 18S rRNA gene of Myxoboluscatmrigalae infecting the gill lamellae of carp, Cirrhinusmrigala and compared its genetic homology and phylogenetic characteristics with 18S rRNA genes of other Myxobolus spp. The infected fish had up to 3 small, creamy white plasmodia per gill filament with 30-50 spores each. The spore size was 17.90 ± 0.70 × 7.40 ± 0.40 μm. The sporoplasm contained two large nuclei of size 0.57 ± 0.09 μm and no iodinophilous vacuole. The DNA sequence of M.catmrigalae was clustered phylogenetically with other Myxobolus spp. infecting the gills of cyprinids available in GenBank, which showed 77-87 % homogeneity. On the phylogenetic tree, M.catmrigalae (KC933944) was clustered with M.pavlovskii (HM991164) infecting the gill lamellae of silver carp, Hypophthalmichthysmolitrix. The species most closely related to M.catmrigalae in GenBank was M.pavlovskii (AF507973) infecting the gill lamellae of big head carp, Aristichthysnobilis with 87 % homogeneity. This is the first report on molecular characterization of gill lamellae infecting M. catmrigalae.

The present work was conducted to isolate and identify different parasites from Indian Major Carp (IMC) Catla catla. During the study period the severity of infection and Parasitic Frequency Index (PFI, %) were also estimated in terms of months, seasons and length groups of fishes. For the investigative purpose different districts of West Bengal were selected considering the potential of fishery resources. Approximately 300 fishes were observed during the entire period of observation. The parasite infested fishes were found to suffer mainly from respiratory manifestations, blackness of the skin and mortalities. The isolated parasites were Myxobolus, Thelohanellus, Trichodina, Dactylogyrus, Gyrodactylus, Nematodes, Argulus, Lernea and Chilodonella species. Besides these, developmental stages of different parasites were also found. Among these parasites Myxobolus, Dactylogyrus and Gyrodactylus showed the highest prevalence in winter. Remaining all parasites was found to be more during spring season. The 1-30 cm length group fishes were found to be more infested with the parasites compare to 30.5-40 cm length groups.

Transportation of fish, although stressful, is an inevitable procedure in aquaculture practices. In this study, we investigated the changes in biochemical and haematological indices in advanced fingerlings of rohu, Labeo rohita in order to optimize the packing density as is imperative to avoid transportation stress and associated mortality . The fish (14.00–15.00 cm) were packed in sealed double layer oxygen packed polythene bags of 30 L capacity containing 7.5 L of water and transported for 2 h and 30 min in a motor vehicle at three packing densities, viz., 67 g L −1 , 134 g L −1 , and 201 g L −1 and transported from hatchery to Kolkata, India covering a distance of about 55 km. A cumulative mortality of 30% was recorded during and after transportation in fish transported at 201 g L −1 ; while the other two packing densities recorded no mortalities. Transportation and packing density induced stress affected the functioning of liver and kidney. The activities of transaminases and lactate dehydrogenase, breakdown of protein and creatinine phosphate, cortisol induced glucose production were significantly increased in advanced rohu fingerlings to cope with the energy demand posed by transportation and higher packing density stress. Low levels of dissolved oxygen and high levels of ammonia-nitrogen were noticed in different packing densities after transportation. The results suggested that the optimum packing density for advanced rohu fingerlings for 2–3 h duration of transport would be 134 g L −1 , which kept the stress at low levels. The serum alanine aminotransferase levels can serve as a good marker for fish liver health as the increment was more prominent when subjected to transportation stress.

Antibiotics are very important tools for the control of fish bacterial diseases. Yet, there are strict regulations controlling the use of antibiotics in aquaculture. This study assessed the efficacy oxytetracycline dihydrate (OTC) at a dose of 2 g, 4 g, 6 g and 8 g/100 pounds fish/day against Aeromonas hydrophila challenge in Nile tilapia Oreochromis niloticus as well as the histopathological alterations in kidney and muscle, and wound healing. The commercial pellet feed was top dressed with OTC using 5 ml vegetable oil as a binder. The fish were injected intramuscularly with A. hydrophila at ≈1 × 108 cells/fish and then fed OTC feeds at 2% of their body weight for 10 days. The fish fed with 8g OTC/100 pounds fish/day recorded the lowest mortality (3.33%). The untreated fish recorded 8.33% mortality. Histologically, the kidney tissues of O. niloticus exhibited nephropathy and glomerulopathy. The kidney of OTC fed groups had improved organization of nephritic tubules and glomerulus. The muscle tissues exhibited haemocyte infiltration with mild necrosis initially, followed by melanization and disrupted muscle bundles. The results demonstrated that the OTC treatment for 10 days could bring out improved functioning of fish kidneys that carry infectious agents. Within 3 days of OTC therapy, tissue reddening and inflammation subsided with the formation of black scar. Full recovery of normal skin architecture was reached within 26-31 days post-injection. Based on the results, prudent use of 4-8 g OTC/100 pounds fish/day is recommended for the control of A. hydrophila infection in O. niloticus.

As new pathogenic strains are emerging and threatening aquaculture development, myxosporeans (Myxozoa) are receiving much attention in recent years. Myxosporean taxonomy is traditionally based on morphology of the myxospore stage. Molecular data on Indian myxosporeans are rare. In this report, the 18S rRNA gene sequence of Myxobolus cuttacki infecting gill lamellae of minor carp Labeo bata (Ham.) and its phylogenetic relationship with other myxobolids are described for the first time. The plasmodia of M. cuttacki were 0.5-0.9 mm in size and whitish with a round to oval shape. The mean mature spore size was 16.10×7.05 μm. The 18S rRNA nucleotide sequence with 1703 bp of M. cuttacki (accession number KF465682) clustered phylogenetically with other Myxobolus spp. infecting cyprinid gills with 78-90% homogeneity. The gill lamellae infecting M. catmrigalae (KC933944) and M. orissae (KF448527) of Indian major carp Cirrhinus mrigala from India, exhibited 86% and 81% homogeneity with M. cuttacki, respectively. The infection rate was low to moderate on the gills which can have a negative impact on respiratory and physiological functions and subsequently on fish production.

Myxosporeans are best known for the diseases they cause in commercially important fish species. Identification of myxosporeans at the species-level is mainly based on conventional methods. The 18S rRNA gene sequence of morphologically identified Myxobolus orissae infecting the gill lamellae of mrigal carp Cirrhinus mrigala was characterized in the present study. The plasmodia of M. orissae were small, elongated and white to pale in colour. Phylogenetically, the 18S rDNA nucleotide sequence of M. orissae was clustered with other gill-infecting Myxobolus spp. of cyprinids. The species closely related to M. orissae was M. koi (FJ841887) infecting the gill lamellae of Cyprinus carpio with 96% similarity. The carp fin-infecting Thelohanellus caudatus (KC865607) from India exhibited only 78% DNA sequence similarity with M. orissae. Low level of M. orissae infection on gill caused thickening of epithelial cells surrounding the plasmodium. Under stressful conditions, it is likely that such infection can easily spread in confined fish and may cause serious disease outbreaks and economical losses.

In this study, the magnetohydrodynamics (MHD) boundary layer flow with heat and mass transfer over a vertical infinite plate in a rotating system with periodic suction has been investigated. The system is placed in porous medium and the plate is subjected to heat source or sink. The model problem is solved numerically by the Crank–Nicolson scheme. The numerical results are presented graphically and the conclusion indicates that the flow field and other quantities of physical interest are significantly influenced by flow parameters.

The freshwater prawn (Macrobrachium rosenbergii) farms and hatcheries of north and south 24 Parganas districts in West Bengal were surveyed for the details of antibiotics and disinfectants used for controlling the prawn diseases and pathogens. During the survey, 4antibiotics and four 4disinfectants were found to be used commonly by the farmers during a 12-month period of study. The chemicals used in the culture systems as antibiotics or disinfectants for the culture water, tanks, other utensils, and others have serious health hazards for both the cultured prawns and human beings. The study also indicates no herbal medicines, and probiotics are being used in prawn farms.

Gadadhar Dash Department of Aquatic Animal Health, Faculty of Fishery Sciences, West Bengal University of Animal and Fishery Sciences, 5, Budherhat Road, Chakgaria, Kolkata700094, West Bengal, India Biraj Bikash Sharma Department of Aquatic Animal Health, Faculty of Fishery Sciences, West Bengal University of Animal and Fishery Sciences 5, Budherhat Road, Chakgaria, Kolkata700094, West Bengal, India.

The present study was conducted from Garia, West Bengal, India to study the Prevalence, Morphology, Severity of infestation and Scanning Electron Microscopy of Myxozoan parasites in Indian Major Carps. A total of 155 fishes were examined, out of which 80 were found infected with myxozoan parasites (51.61 %) and severity of infestation varied from 0.5 to 2. Three known species Myxobolus orissae, M. carnaticus and Thelohanellus caudatus were found infecting various organs such as gills and fins of Indian major carps. Spores of the species, T. caudatus measures 12.84 ± 0.77 (11.4-14.2) μm × 8.5 ± 0.71 (7.6-9.6) μm and was elongated pyriform in shape with rounded posterior and tappering anterior end. Parietal folds were absent. The single polar capsule is rounded to oval shaped with slightly pointed anterior end and broad posterior end with size measuring 6.15 ± 2.09 (4.2-10.4) μm × 3.85 ± 1.18 (2.3-4.9) μm. M. orissae, size of the mature spore measures 15.6-19.7 (17.25) μm × 5.7-9.3 (6.70) μm and was elongated pyriform in shape. Two polar capsules are distinctly unequal. Large one measures 6.8-13.5 (8.75) × 1.4-3.1 (1.90) μm and smaller one 6.9-11.5 (7.44) × 1.7-2.4 (1.57) μm in size. Both are broadly pyriform with pointed pointed anterior end and rounded posterior end. Myxobolus carnaticus mature histozoic spores measures 8.1-12.9 (9.49) × 7.2-10 (8.27) µm are creamy white to yellow in colour tear shaped in valvular view with rounded posterior and bluntly pointed anterior ends.

The present study attempted sequencing the 18S rRNA gene of Myxobolus catmrigalae infecting the gill lamellae of carp, Cirrhinus mrigala and compared its genetic homology and phylogenetic characteristics with 18S rRNA genes of other Myxobolus spp. The infected fish had up to 3 small, creamy white plasmodia per gill filament with 30–50 spores each. The spore size was 17.90 ± 0.70 × 7.40 ± 0.40 μm. The sporoplasm contained two large nuclei of size 0.57 ± 0.09 μm and no iodinophilous vacuole. The DNA sequence of M. catmrigalae was clustered phylogenetically with other Myxobolus spp. infecting the gills of cyprinids available in GenBank, which showed 77–87 % homogeneity. On the phylogenetic tree, M. catmrigalae (KC933944) was clustered with M. pavlovskii (HM991164) infecting the gill lamellae of silver carp, Hypophthalmichthys molitrix. The species most closely related to M. catmrigalae in GenBank was M. pavlovskii (AF507973) infecting the gill lamellae of big head carp, Aristichthys nobilis with 87 % homogeneity. This is the first report on molecular characterization of gill lamellae infecting M. catmrigalae.

The entitled book “Freshwater Fish Parasites” spread over 10 s, with complete pictorial guide of different fresh water fish parasites all over the country. The detail etiology, clinical signs , prophylaxis and treatment of parasitic diseases have been discussed in a simplified manner for easy understanding of students,researchers,teachers,scientists and farmers in the field .The book covers most interesting s and will guide to identify and manage parasitic diseases including some aspects of latest developments in fish parasitological research. A comprehensive approach has been made to cover all the progressive areas of parasitic disease management starting from identification of the parasites, basic status of diseases towards various approaches to diagnose, prevent and control disease conditions. The parasitic problems of different fishes, like indigenous fishes, exotic fishes of commercial importance, sport fishes and ornamental fishes have been addressed to give a complete parasitic disease profile on total fishery. The behavior of the hosts, interrelationship of soil and water with parasitized hosts, and mechanism of parasitic attachment are important aspects of the concerned book.

The study was conducted to investigate the histological changes of vital organs such as kidney, gills and brain with the mixed infestation of parasites in Indian Major Carps (IMC). The parasites such as Myxobolus spp., Thelohanellus spp., Trichodina spp., Dactylogyrus spp., Gyrodactylus spp. and Nematodes were observed in three IMC. Several histological alterations were observed in the kidney of Catla catla, Labeo rohita and Cirrhinus mrigala, which includes vacuolar degeneration in the epithelium of renal tubules, focal areas of necrosis, proliferation of bowman's capsule and many cases the renal tubules lost its shape and canalculi formation was observed. The gills showed focal areas of necrosis, exacerbated swelling of gill arch, deposition of distinct black melanin pigmentation at the basal point of the gill arch, loss of primary and secondary lamellae, prominent vacuolar degeneration and formation of vacuoles. The presence of protozoan parasites in brain tissue resulted necrosis of the brain tissue, black pigmentation, vacuolization of myelin sheath of nerve fibers and common degenerative changes. Aims: To study histological changes of vital organs such as kidney, gills and brain with the mixed infestation of parasites in Indian Major Carps (IMC). Settings and Design: The organs fixed in 4% formalin are transferred to 50% ethyl alcohol and stored for further analysis. Materials and Methods: Histopathological analysis was made as described by Roberts. Statistical Analysis Used: Nil. Results: Described in text. Conclusions: The present study brings about conclusion that impact of mixed infestation of the parasites on their hosts was severe. Histopathological changes were observed in vital organs which might be due to toxins released by different parasites or physical damage of tissue with the presence of parasites.

The study has been carried to find out the distribution of different parasites in Exotic carps with respect to different months and seasons. These were isolated and identified from the fishes sampled randomly from five fish markets, which were representing South 24 parganas district, West Bengal. During the study period ten different types of parasites were observed such as Trichodina sp, Chilodonella sp, Trichinella sp., Acanthocephala sp, Nematodes, Epistylis sp, Zoothamnium sp, Vorticella sp, developmental stages of eggs or parasites and some parasites (unidentified) among which most of the parasites were protozoan. Among all the parasites the most dominant were Trichodina sp, Chilodonella sp and Nematodes. Winter was the most vulnerable period to get parasitic infestation. During this period the water quality get deteriorated and the fishes were in stressed condition which favours the parasites to infest. Some parasites were found more during summer which favours their reproduction due to the availability of their intermediate host. In monsoon the temperature fluctuates which also favours growth of some parasites. During the study period Trichinella sp were found solely in Cyprinus carpio exclusively in winter.The protozoan parasites were most available during winter and these were the dominant parasites in exotic carps. These parasites were found mostly on gills and skin of the fishes where as nematodes were found in the intestine and body cavity of the fishes.

Background: Histopathological changes induced by a rise in the acclimation temperature in advanced Labeo rohita (Hamilton) fingerlings were studied to understand their adaptive ability to thermal changes. The histopathological changes in relation to the thermal changes have been widely used as bioparameters in the evaluation of fish health. Materials and Methods: The six experimental temperatures that the fishes were exposed to were 32, 34, 36, 38, and 40oC for a period of 30 days each. The fishes kept at an ambient temperature of 29.3΁1.5oC were used as control. The major organs studied were gills, liver, kidney, and heart. No specific alterations were observed at control, 32, and 34oC. The organs were sampled at the end of 30 days exposure and histopathological changes of different organs were examined. Result and discussion: Different organs (gill, liver. Kidney and heart) show different histopathological changes in higher temperatures. However, adaptive and degenerative changes were found to occur at the higher temperatures of 36, 38, and 40oC. Conclusions: Changes of temperature can be tolerated by the fishes and it brings about adaptive physiological changes to compensate the effects of temperature. Significance: The study was helpful; to understand the adaptive mechanisms used by fishes with changes of environmental temperatures.

The lucrative business of ornamental fish culture in West Bengal (Mainly in three districts-Howrah, North and South 24 Parganas) are facing loses due to the invasion of different ecto- and endo-parasites. The present study shows that the ornamental fish (Goldfish - Carassius auratus) are mainly affected with ecto-parasites like Ichthyophthirius sp., Dactylogyrus sp., Gyrodactylus sp., Argulus sp. and endo-parasites like Procamallanus sp. and Cucullanus sp. The intensity of infection is high in case of Ichthyophthirius sp. and the intensity of the infection is high in summer months when the temperature is high or moderately high. In cooler months the intensity of the infection is lower as because the parasites are unable to breed or scarcity of food particles.