Ornamental Fish Farms Research Articles

Detection of Saprolegnia parasitica in eggs of angelfish Pterophyllum scalare (Cuvier–Valenciennes) with a history of decreased hatchability

Mass mortalities of angelfish eggs accompanied with very low hatchability were reported in a private ornamental fish farm in Egypt. Examined eggs were badly damaged by water mould that was decisively confirmed as Saprolegnia species. Presumptive identification of the ten retrieved isolates was initially suggestive of Saprolegnia species. Mycological investigations have revealed that only 7 out of 10 isolates were capable of producing sexual stages. Therefore, using molecular tools such as PCR coupled with partial sequencing of inter-transcribed spacer (ITS) gene was one of the most important approaches to distinguish Saprolegnia parasitica from other water moulds. The sequences of ITS gene data derived from eight isolates showed 100% similarity with S. parasitica ATCC90312 sequence and the remaining two isolates were different in one nucleotide (99.9%). The phylogenetic analysis of ITS genes grouped the ten isolates with other S. parasitica in one clad. Further, to control such fungal infection, the efficacy of povidone iodine as surface disinfectant for angelfish and their fertilized eggs were tested. By trial, it was obvious that the obtained post-rinsing results were highly suggestive for the efficacy of povidone iodine as an efficient antifungal disinfectant for both fish and eggs.

FEED FORMULATION AND FEEDING TECHNOLOGY FOR FISHES

Most fish farmers and ornamental fish hobbyists buy the bulk of their feed from commercial manufacturers. However, small quantities of specialized feeds are often needed for experimental purposes, feeding difficult - to maintain aquarium fi shes, larval or small juvenile fishes, brood fish conditioning, or administering medication to sick fish. S mall ornamental fish farms with an assortment of fish require small amounts of various diets with particular ingredients. It is not cost effective fo r commercial manufacturers to produce very small quantities of specialized feeds. Most feed mills will only produce custom formulations in quantities of more than one ton, and medicated feeds are usually sold in 50 - pound bags. Small fish farmers, hobbyists and laboratory technicians are, therefore, left with the option of buying large quantities of expensive feed, which often goes to waste. Small quantities of fish feed s can be made quite easily in the laboratory, classroom, or at home, with common ingredie nts and simple kitchen or laboratory equipment. Hence, t his review provide s the knowledge about the fish feed formulation and feeding technology concerned with the live feed for fish larvae, fish f ee ds, fish feed ingredients, common fish feed stuff s , anima l and plant sources of feeds for culture fish, and fish feeding methods .

Asian aquarium fishes in a Neotropical biodiversity hotspot: impeding establishment, spread and impacts

We provide evidence of reproductive activities of nine Asian freshwater fish species belonging to three families in Atlantic Forest creeks located in the Paraiba do Sul River basin, southeastern Brazil, an area rich in endemic and endangered fish fauna. These non-native fishes were introduced into the natural systems by both accidental and intentional releases from ornamental fish farms in the region. Adults of all species were found reproducing during virtually all year round and showed fractionated spawning. Imature individuals (young-of-the-year and juveniles) were also frequent in the five sites. Most of the total sex ratios were close to 1:1. The frequent releases, warm water temperature, marginal vegetation providing food, protection and spawning sites, and the low richness of native fishes in these creeks can facilitate the establishment process of all species. The creeks can also act as dispersing agents of non-native fishes after flash floods, leading to biotic homogenization or differentiation in the local fish community, competition with native fishes, and parasite dissemination. Given the flourishing aquaculture activity in the area, it is expected that these and other non-native species cause extensive modifications in the regional ichthyofauna.

The use of antibiotics and disinfectants in ornamental fish farms of West Bengal, India

The use of antibiotics and disinfectants in ornamental fish farms of West Bengal, India

<b>Reprodução da exótica rã-touro Lithobates catesbeianus (Shaw, 1802) (Amphibia, Anura, Ranidae) em riachos de Mata Atlântica no estado de Minas Gerais, Brasil</b><br>doi: 10.5007/2175-7925.2010v23n3p85

Reproduction of the exotic bullfrog Lithobates catesbeianus was studied every two months from January 2005 to December 2006, analyzing tadpoles, juveniles, and adult vocalizations at three creeks located in the largest Brazilian center of ornamental fish breeding. Absolute and relative tadpole frequencies were measured bimonthly in three development stages: G1 (no limbs), G2 (hind limbs present), G3 (fore and hind limbs) and I (metamorphs). Results show that, during warmest months, a greater proportion of tadpoles in G1, G2, and G3 phases were found in Santo Antônio and Chato creeks, while G1, G3, and I phases were more common in Gavião creek. Tadpoles in G1 and G2 phases predominated in coldest months at all locations. Male calls and highest average water temperatures and rainfall were recorded at 3 streams during the hottest months. Management measures should be adopted, such as the extermination of larval and adult stages, and initiatives should be taken to prevent new re-introductions, such as: (1) installation of fences around tanks where adults are located, (2) placement of protective screens on the pipes that release waste water from tanks directly into streams, (3) capacity building and educational measures on the problems of biological invasions for staff working on ornamental fish farms.

Antimicrobial resistance and its genetic determinants in aeromonads isolated in ornamental (koi) carp (Cyprinus carpio koi) and common carp (Cyprinus carpio)

The aim of this study was to evaluate antimicrobial susceptibility of Aeromonas spp. isolates from common carp and koi carp coming from randomly chosen farms. The isolates were tested for susceptibility to 8 antimicrobial agents using the standard agar dilution susceptibility test. In all isolates, PCR was used to detect the presence of tet(A-E) genes, integrase genes, and gene cassettes. From the total 72 isolates of motile aeromonads sampled from koi carp, 36 isolates (50%) were resistant to oxytetracycline, 18 (25%) to ciprofloxacin, 5 (7%) to chloramphenicol, 5 (7%) to florfenicol, and 11 (15%) to trimethoprim. Among 49 isolates of motile aeromonads collected from common carp, 20 (41%) were resistant to oxytetracycline, 3 (6%) to chloramphenicol, and 3 (6%) to florfenicol. The resistance of aeromonads isolated from koi carp was significantly higher to ciprofloxacin (P=0.00024). The presence of class 1 integrons was detected in these isolates only (P=0.00024). Tet genes were detected in 40% (48/121) of isolates, with tet(E) being the most dominant. Our results demonstrated a significant difference in the incidence of resistant isolates collected from koi carp and common carp (P=0.00042). This difference can be ascribed to a distinct antibiotic policy established on consumer fish farms versus ornamental fish farms. The potential risk for resistant bacteria to spread and transmit infection to humans should be considered in cases of technological crossover between the two types of fish farms.

Cysteine proteases and acid phosphatases contribute to Tetrahymena spp. pathogenicity in guppies, Poecilia reticulata

Systemic tetrahymenosis caused by the protozoan parasite Tetrahymena spp. is a serious problem in guppy ( Poecilia reticulata) farms worldwide. There is no therapeutic solution for the systemic form of this disease. Guppies severely infected with Tetrahymena spp. were imported by a commercial ornamental fish farm and brought to our laboratory. Tetrahymena sp. (Tet-NI) was isolated and in vitro cultured. Isolates maintained in culture for different time periods (as reflected by different numbers of passages in culture) were analyzed—Tet-NI 1, 4, 5 and 6, with Tet-NI 1 being cultured for the longest period (about 15 months, 54 passages) and Tet-NI 6 for the shortest (2.5 months, 10 passages). Controlled internal infection was successfully achieved by IP injection with most isolates, except for Tet-NI 1 which produced no infection. The isolate Tet-NI 6 induced the highest infection rates in internal organs (80% vs. 50% and 64% for Tet-NI 4 and 5, respectively) and mortality rates (67% vs. 20% and 27% for Tet-NI 4 and 5, respectively, and 6.7% for Tet-NI 1). The correlation between pathogenicity and Tetrahymena enzymatic activity was studied. Electrophoretic analyses revealed at least two bands of gelanolytic activity in Tet-NI 4 and 5, three bands in Tet-NI 6, and no activity in Tet-NI 1. Total inhibition of gelanolytic activity was observed after pretreatment of Tet-NI 6 with E-64, a highly selective cysteine protease inhibitor. Using hemoglobin as a substrate, Tet-NI 6 had two bands of proteolytic activity and no bands were observed in Tet-NI 1. A correlation was observed between pathogenicity and acid phosphatase activities (analyzed by commercial fluorescence kit) for Tet-NI 1 and Tet-NI 6.

Molecular Analysis of Spring Viraemia of Carp Virus in China: A Fatal Aquatic Viral Disease that Might Spread in East Asian

Spring viraemia of carp (SVC) is a fatal viral disease for cyprinid fish, which is caused by spring viraemia of carp virus (SVCV). To date, no SVC outbreak has been reported in China. Between 1998 and 2002, outbreaks of SVC were reported in ornamental and wild fish in Europe and America, imported from multiple sources including China. Based on phylogenetic analysis, the viral strain isolated from America was shown to be originated from Asia. These outbreaks not only resulted in huge economic losses, but also raise an interesting question as to whether SVCV really exists in China and if so, is it responsible for SVC outbreaks? From 2002 to 2006, we screened 6700 samples from ornamental fish farms using the cell culture method of the Office International des Epizooties (OIE), and further verified the presence of SVCV by ELISA and real-time quantitative RT-PCR. Two infected samples were found and the complete genome of SVCV was sequenced from one of the isolates, termed SVCV-C1. Several unique hallmarks of SVCV-C1 were identified, including six amino acid (KSLANA) insertion in the viral RNA-dependent RNA polymerase (L) protein and ten nucleotide insertion in the region between glycoprotein (G) and L genes in European SVCV strains. Phylogenetic tree analysis of the full-length G protein of selected SVCV isolates from the United Kingdom and United States revealed that G proteins could be classified into Ia and Id sub genogroups. The Ia sub genogroup can be further divided into newly defined sub genogroups Ia-A and Ia-B. The isolates derived from the United States and China including the SVCV-C1 belongs to in the Ia-A sub genogroup. The SVCV-C1 G protein shares more than 99% homology with the G proteins of the SVCV strains from England and the United States, making it difficult to compare their pathogenicity. Comparison of the predicted three-dimensional structure based on the published G protein sequences from five SVCV strains revealed that the main differences were in the loops of the pleckstrin homology domains. Since SVCV is highly pathogenic, we speculate that SVC may therefore pose a serious threat to farmed cyprinid fish in China.

Protozoan parasites of Xiphophorus spp. (Poeciliidae) and their relation with water characteristics

This work investigated the relationship between water characteristics and infestation of protozoan parasites, Icthyophthirius multifiliis and Trichodina sp., in swordtails (Xiphophorus helleri) and platy (Xiphophorus maculates) collected in an ornamental fish farm in São Paulo, Brazil. Fish were monthly collected from ponds and tanks for one year. The prevalence rates in fish from tanks and ponds were, respectively, 34.2% and 22.5% for I. multifiliis, and 13% and 54.2% for Trichodina sp. Increased electric conductivity and pH provoked reduction of I. multifiliis infestation. Low oxygen concentration increased Trichodina sp. infestation. The use of salt to increase the electric conductivity of water was a method to control I. multifiliis. Low dissolved oxygen and the addition of organic fertilizer favored the reproduction of Trichodina sp.

Camallanus maculatus n. sp. (Nematoda: Camallanidae) in an ornamental fish Xiphophorus maculatus (Osteichthyes: Poeciliidae) cultivated in São Paulo State, Brazil

The present study describes Camallanus maculatus n. sp. (Nematoda: Camallanidae) from Xiphophorus maculatus (Osteichthyes: Poecilidae) collected in an ornamental fish farm in São Paulo State, Brazil. Thirty-three out of 40 examined fish were parasitized (82% prevalence) with mean intensity of 2.8 (1-20). Male specimens were 3,500µm total length and females 7,100µm total length, provided with orange-brown buccal capsule and two developed tridents. Males showed two unequal spicules, gubernaculum absent and females with vulva situated in the middle of the body. The main characteristics were the sleekly longitudinal ridges in the buccal capsule in both sexes, enlargement at the anterior end of the smaller spicule, the number of genital papillae, longer muscular and glandular portion of esophagus and round tail in female.

Preliminary Morphometrics of Spleen and Kidney Macrophage Aggregates in Clinically Normal Blue Gourami Trichogaster trichopterus and Freshwater Angelfish Pterophyllum scalare

Macrophage aggregate (MA) morphometry and pigment composition are believed to be dependent on the species, age, and health status of the fish. The aim of this study was to characterize a "normal" morphometry baseline of spleen and kidney MAs in blue gourami Trichogaster trichopterus and freshwater angelfish Pterophyllum scalare. Three size-classes of clinically normal fish were analyzed. Blue gourami and freshwater angelfish were obtained from three local ornamental fish farms; for each size-class, 10 fish from each farm were analyzed. Hematoxylin- and eosin-stained tissue sections were analyzed by light microscopy at 100x magnification and an image analysis program. The percentage of tissue occupied by MAs, MA size, and MA number were calculated on three arbitrarily selected fields of view from each spleen and kidney. In clinically normal blue gourami, increases in the percentage of tissue occupied by MAs and in MA size were associated with an increase in fish size, but in clinically normal angelfish no correlation was observed. Furthermore, in angelfish, a high variability in MA morphometry was observed, even among fish from the same sample group. In both species, a significant difference in the value of the morphometric parameters was observed among farms. Because iridoviruses inhibit macrophage activity and (possibly) proliferation, MAs in 25 clinical cases of iridovirus-infected blue gourami were analyzed. Preliminary data indicate that in iridovirus-infected blue gourami, there is a decrease in MA size and MA number compared with those of healthy fish.

Characterization of Streptococcus iniae isolated from ornamental cyprinid fishes and development of challenge models

Streptococcus iniae was isolated from red-tail black shark(RTB shark) Epalzeorhynchos bicolor, and rainbow shark, E. erythrurus (fam: Cyprinidae), obtained from a local freshwater ornamental fish farm in Hillsborough county (FL). Darkening of the skin and lethargy were the first signs observed in infected sharks. Hemorrhages were observed on the ventral side of the body, on the head, and at the base of the pelvic and pectoral fins. Exophthalmia was observed in a low percentage of fish (∼ 10%). Moribund fish demonstrated the characteristic spinning, swimming pattern observed during streptococcal infections. Histological analysis revealed leukocyte infiltration in the intestinal area, spleen, posterior kidney, and brain. Necrosis and tissue degeneration were observed in the same organs in addition to degeneration of the renal tubules. Gram positive cocci were isolated from the cultures of brain and kidney tissues. Bacterial identification was obtained with the BIOLOG MicroLog3 version 4.00 System (Biolog, Inc., Hayward, California) and with standard microbiological tests. S. iniae-free RTB and rainbow sharks were used for developing a challenge model with the isolated bacteria strain. The experiments were conducted in two separate recirculating systems each with 25 tanks, 38 L volume per tank. In all experiments, the water in the system was maintained at 25 ± 1 °C. For each treatment, there were 3 replicate tanks, each stocked with 25 fish. Tanks were randomly assigned to treatment or control groups. Sharks were challenged by intracoelomic injection of S. iniae, and mortality was recorded for 14 days. Moribund fish showed classical signs of streptococcosis and S. iniae was isolated from moribund and dead fish. Differences in susceptibility to S. iniae were observed between the two species. An injection of 1.5 × 10 4 colony forming units (CFUs)/fish caused mortality close to 70% in RTB shark, and a higher mortality rate in rainbow shark. Mortalities ceased in 11–12 days after bacterial challenge in RTB shark, and in 3–4 days in rainbow shark. In this report, the pathology of S. iniae infections in two ornamental freshwater sharks and the development of a challenge model are described.

Escapees of potentially invasive fishes from an ornamental aquaculture facility: the case of topmouth gudgeon Pseudorasbora parva

Accidental escapees from aquacultural facilities are an ongoing problem facing scientists, conservationists, policy makers and naturalists throughout the world. The topmouth gudgeon Pseudorasbora parva, a small cyprinid native to Southeast Asia, was introduced to Romanian waters in 1960 via the aquaculture trade and has since spread throughout Europe. It first appeared in England in an ornamental fish farm near Romsey in Hampshire. The aim of the present study was to quantify the dispersal of this potentially highly invasive species from an ornamental fish farm into the wild. In order to measure the dispersal of escapees, intensive electrofishing surveys were carried out between June and September 2003 in the catchment downstream of the fish farm. The distribution of topmouth gudgeon in the catchment was found to be limited and patchy. The presence of small individuals suggests that the species has successfully established itself in the wild, but this remains to be confirmed. The results were examined in light of invasion theory principles of biological resistance and ecological fitness.

Transforming open mining pits into fish farms: Moving towards sustainability

Abstract The legacy of mining activities has typically been land ‘returned to wildlife’, or, at some sites, degraded to such an extent that it is unsuitable for any alternate use. Progress towards sustainability is made when value is added in terms of the ecological, social and economic well‐being of the community. In keeping with the principles of sustainable development, the innovative use of flooded open pits and tailings impoundments as commercial, recreational or ornamental fish farms should be considered in some locations, as it could make a significant contribution to the social equity, economic vitality and environmental integrity of mining communities. This article highlights the growing significance of aquaculture and explores the benefits and barriers to transforming flooded pits and impoundments into aquaculture operations. Among other benefits, aquaculture may provide a much‐needed source of revenue, employment and, in some cases, food to communities impacted by mine closure. Further, aquaculture in a controlled closed environment may be more acceptable to critics of fish farming who are concerned about fish escapes and viral transmissions to wild populations. Despite the potential benefits, aquaculture in flooded pits and impoundments is not without its complications — it requires a site‐specific design approach that must consider issues ranging from metals uptake by fish, to the long‐term viability of the aquatic system as fish habitat, to the overall contribution of aquaculture to sustainability.

Recent developments in the application of live feeds in the freshwater ornamental fish culture

The industrial development of freshwater ornamental fish culture has been hampered by the lack of suitable live feeds for feeding the fish at the various production stages. This paper reports the recent developments in the applications of the freshwater rotifers ( Brachionus calyciflorus), Artemia nauplii, decapsulated Artemia cysts and on-grown Artemia in the freshwater ornamental fish culture. Results demonstrate that the rotifers are an ideal starter feed for dwarf gourami ( Colisa lalia), a typical freshwater ornamental fish species with larvae that are too small to ingest Artemia nauplii or Moina at its first feeding. Compared with the conventional yolk food, the use of rotifers as a starter feed significantly improves the growth and survival of the gourami larvae (Days 2–12), and the beneficial effects are extended to the subsequent Artemia-feeding phase (Days 13–32). The freshwater rotifers and Artemia nauplii are also useful in raising Discus larvae in the absence of their parents, which would eliminate the risk of larvae being eaten by the parent fish. Work on decapsulated Artemia cysts indicates that the cysts could be used as a substitute for Artemia nauplii or Moina in freshwater ornamental fish culture. The fry of all the five common ornamental fish species tested (guppy Poecilia reticulata, molly Poecilia sphenops, platy Xiphophorus maculatus, swordtail Xiphophorus helleri and neon tetra Hyphessobrycon herbertaxelrodi) could readily feed on the decapsulated cysts, and their performances in terms of stress resistance, growth and survival are comparable to or better than those fed on Artemia nauplii or Moina. A culture system for production of on-grown Artemia has also been developed specifically for the use in freshwater ornamental fish farms. The system, using diluted artificial seawater of 20‰ for culture, has a mean production rate of 3 kg/m 3 of water in a 12-day cycle and a production capacity of 8 metric tons of on-grown Artemia a year. With the system, farmers could produce any specific size of on-grown Artemia of up to 5 mm to suit the age and size of their fish, by varying the time of harvesting. This characteristic, coupled with the use of bioencapsulation technique to enhance the quality of the on-grown Artemia, would make the organism an ideal nursery diet for freshwater ornamental fish. All these results show that the live feeds used in marine foodfish hatchery could be applied to freshwater ornamental fish culture to improve their performance.

Limited water exchange production systems for freshwater ornamental fish

Two biofilter designs and a control were tested in triplicate to determine if inexpensive bioremediation devices could increase production and decrease water use on ornamental fish farms in Hawaii. Koi (Cyprinus carpio L.) were used as the model species and the experiment was conducted outdoors in greenwater. When fish density was 9.7 kg per 2.08 m3 and they were eating 125 g day−1, the 20 L trickle filters were able to maintain acceptable water quality. Tanks with the same size submerged filters suffered significantly lower dissolved oxygen levels compared with tanks with trickle filters and control tanks with no biofilters exhibited significantly higher nitrite-nitrogen (about 20 mg L–1) and nitrate levels (about 400 mg L–1). As typical ornamental fish weigh 3 g, the trickle biofilter system described here can produce 1.55 fish L−1 (compared with the industry standard 0.25 fish L−1) and use very little water other than the water originally in the tanks.

Iridovirus infections in farm-reared tropical ornamental fish

A systemic viral infection in both gourami Trichogaster spp. and swordtail Xiphophorus hellerii and an outbreak of lymphocystis in scalare Pterophyllum scalarae and gourami are reported to have occurred in fish reared in ornamental fish farms in Israel. The systemic infection developed in endothelial cells that became hypertrophic and their contents were modified. The presence of such cells in light-microscopically examined stained smears and sections provides an initial indication for this systemic viral infection. Infection in gourami caused hemorrhagic dropsy. Transmission electron microscopic (TEM) images of iridovirus-like particles recovered from gouramies showed them to be 138 to 201 nm from vertex to vertex (v-v); those from swordtails were 170 to 188 nm v-v. TEM images of lymphocystis virions from scalare were 312 to 342 nm v-v and from gourami 292 to 341 nm v-v. Lymphocystis cells from the gourami were joined by a solid hyaline plate, which was lacking in the infection in scalare where the intercellular spaces between the lymphocystis cells consisted of loose connective tissue.

Production and application of on‐grown Artemia in freshwater ornamental fish farm

This paper describes a pilot culture system for the production of on‐grown Artemia in freshwater ornamental fish farms. The system had 21 culture units, each consisting essentially of three components: an oval‐shaped raceway, an air‐water lift system and two waste collectors. Using artificial seawater at 20 ppt for culture and at a mean production rate of 3 kg/m3 of water in a 12‐day cycle, the system had a production capacity of 8 metric tons of on‐grown Artemia a year. Biochemical analyses were preformed to evaluate the nutritional value of the on‐grown Artemia against three conventional live feeds, viz. live Artemia nauplii, live Moina and frozen bloodworms. Cost‐benefit analysis showed that with a capital investment of US$ 82,000 and an annual cost of production of US$ 81,000, the system achieved a high internal rate of return of 88% over a 10‐year period and a short payback period of 1.23 years. The availability of on‐grown Artemia would not only offer farmers and exporters a better alternative live food organism for feeding to their fish, but more importantly the possibility of enhancing the fish performance and quality through bioencapsulation.

Acid-fast bacterial infection and its control in guppies (Lebistes reticulatus) reared on an ornamental fish farm in Venezuela

There was a spontaneous outbreak of mycobacteriosis in fancy veiltail guppies, Lebistes reticulatus, raised on an ornamental fish farm in Venezuela. The clinical signs included listlessness, emaciation, spinal curvature, sunken...

Evaluation of aquaculture effluents

Water quality data were collected from six Department of Fisheries and Aquatic Sciences (FAS) aquaculture ponds at the University of Florida and two ponds at each of four private farms. Effluents from four of the FAS channel catfish ( Ictalurus punctatus) ponds were treated by pumping the water into a retention pond or vegetated ditch. At the stocking rates used, little relationship existed between harvest densities (kg·ha −1) and water quality parameters; however, harvest densities were lower than in most intensive production systems. Total suspended solids (TSS) were elevated by seining; however, if pumping did not occur immediately after seining, the TSS settled prior to pumping. Passing water through a retention pond or vegetated ditch reduced TSS. Mean water quality parameters in channel catfish fingerling ponds and sportfish (largemouth bass, Micropterus salmoides; bluegill, Lepomis macrochirus; redear sunfish, L. microlophus) fingerling ponds were generally lower than in the food-size channel catfish ponds except for dissolved oxygen. This study was conducted to develop a water quality database from a variety of soil types and cultured species. These data along with data from one catfish farm located in Northwest Florida were evaluated to determine if effluents from these farms meet Florida water quality standards. Using these data, the Florida Department of Environmental Regulation (FDER) developed a general permit for fish farms. Sufficient data from ornamental fish farms were available, and therefore ornamental fish farms were included in the permit without additional data collection.