Current Overview of Ornamental Fish Diseases T.Kumaran Department of Zoology, Muslim Arts College, Thiruvithancode, Kanyakumari District 629174
ABSTRACT The growing interest in aquarium fishes has resulted in steady increase in aquarium fish trade globally. India’s share in global ornamental fish trade is negligible and at present the ornamental fish export from India is dominated by the wild caught species. The Aquaculture Guidelines recognize the fact that responsible development of aquaculture depends on social, economic and environmental sustainability, all of which have to be addressed. They also recognize that there is an extensive national and international legal framework in place for various aspects of aquaculture and its value chain, covering issues such as aquatic animal disease control. Moreover, increased risks of species invasions and the spread of diseases raise additional concerns. Fish diseases could have major impacts on supply, demand and trade in domestic and international markets, as resulting trade restrictions might alter markets for extended periods. The present article provides information on available ornamental fish diseases and explains their aquarium maintenance. Key words: Ornamental fish, Aquaculture, Diseases, * Presenting author # Address for correspondence: kumaranmac@gmail.com Introduction Aquarium keeping is amongst the most popular of hobbies with millions of enthusiasts worldwide. According to FAO (1996-2005), export earnings from ornamental fish trade is US $ 251 million and more than 60% of the production comes from the households of developing countries. The wholesale value of the global ornamental fish trade is estimated to be US$ 1 Billion while the retail value is US$6 Billion. Several diseases of economic importance are recorded and the common diseases, symptoms, and control measures together with treatment protocols are summarized in this paper. Relationship of host, pathogen, and environment
It is generally accepted that all outbreaks of a communicable disease are the result of interaction between the host, the pathogen, and the environment. This is particularly true in regard to fishes, which are coldblooded and utilize oxygen dissolved in water. The environment of the open sea is very stable, but in the inland waters and in fish farms extreme water temperatures, low dissolved oxygen contents, presence of fish catabolic products, and general pollution often produce stresses which contribute to outbreaks of infectious diseases.(Seleye, 1955). Effects of ornamental fish diseases Ornamental fish have also played a minor role in bacterial zoonoses. Isolated cases of septicaemias associated with strains of Edwardsiella tarda, cutaneous mycobacteriosis, liver abscesses and diarrhoea in infants have all been related to ornamental fish (Vaishampayan and others 1996). The greatest losses of wild-caught aquarium fish may occur during the handling period between capture, local exporting/importing warehouses, and transportation docks. While in transit, fish may be subjected to physical injury, extreme changes in water quality conditions, water temperature fluctuations, and indiscriminate exposure to toxic chemicals used as prophylactic treatments for disease control. Also it has been determined that mortality of captured fish from the wild can be species dependant. For example, mortality has been estimated to be high (e.g., 80%) in some marine tropical fish such as the Banggai cardinal fish to a low of 6% for some freshwater fish species such as the cardinal tetra (Chao et al. 2001; Lunn and Moreau 2004). Diseases of ornamental fishes: symptoms. The majority of diseases affecting fishes are infectious, caused by viruses, bacteria, and parasites. If these pathogens multiply in vast numbers in or on the fish, they can cause massive damage to the organism by depriving it of life-essential substances that they require for their own metabolic processes, and/or by producing ichthyotoxic substances as a result of those processes. In both cases the health of the fish is affected and the result is diseases manifesting in a huge variety of symptoms. Another classic example is the spread of goldfish ulcer disease, caused by a typical strains of the alien bacterium Aeromonas salmonicida. This bacterium was first recorded in Australia in 1974 and is thought to have been introduced via infected Japanese goldfish
(Carassius auratus). Aeromonas spp. are ubiquitous aquatic organisms, associated with multitude of diseases in several species of animals, including fishes and humans. (Sreedharan et al. 2012) Before going to diagnosis of fish disease one should know the condition of healthy and unhealthy fish. Healthy fishes generally have clean body; erect fins, bright body colour, bright eyed, faster movement if frightened and skin and fins are in intact conditions. While unhealthy fishes may change of four factors. Common clinical symptoms shows by unhealthy fishes are irregular swimming movement, jumping of the fish, rubbing of the body against any rough substrate, surfacing on water, gasping air, refusal of feed and excessive mucus secretion etc. Abdominal swelling or cyst formation also indicates some internal disorder of fish. Recently, the development of ornamental (koi) carp (Cyprinus carpio koi) farming has appeared in the country, both on small-scale farms and large production farms. Intensive carp farming is associated with risk for the incidence and spread of infectious diseases commonly associated with therapeutic and prophylactic use of antibiotics (Smith, 2008). Common ornamental fish Diseases Diseases
Causative agent
Bacterial diseases Dropsy
A. hydrophila
Fin and tail rot
Pseudomonas sp.
Skin ulcer disease
Psuedomonas aeroginosa
Fungal diseases Cotton wool disease
Saprolegnia
Parasital disease White spot disease
Ichthyophthirius multifiliis
Velvet disease
Oodinium spp
Blue slime disease
Costia necatrix
Whirling disease
Myxosoma cerebralis
Gyrodactylosis
Gyrodactylus sp
Argulosis
Argulus sp.
Control measures of ornamental fish diseases The best method of long-term control is to identify and eliminate the factors responsible for bringing on the disease. Factors causing stress include poor water quality, overstocking, high
temperature, handling and over-feeding. Affected fish should be isolated. Care must be taken with equipment to avoid transmitting the disease between batches. Netting a fish which has an ulcer contaminates the net, and when used again this net rubs the bacteria into the skin of another fish. Disinfection of nets with benzalkonium chloride solution is very worthwhile since it has a detergent action which effectively removes mucus which might protect the bacteria from the effects of a disinfectant. Prompt veterinary involvement can help to minimize losses by David graham. Treatment of fish diseases Affected fish should be placed in a quarantine tank. If the fish are still feeding, a full course of antibiotic medicated flake or pelleted feed can be very beneficial. A course of antibiotic injections is the treatment of choice if large or very valuable fish are involved; bath treatment is generally not worth the cost and is often ineffective. Endo et aI., (1973) reported Misuse of antibiotics has rendered many infectious organisms resistant to treatment with standard antibiotics. Various antibiotics have been used, including the potentiated sulphonamides, neomycin, oxy-tetracycline and oxolinic acid. Once the ulcer has been treated, the fish can be held in a salt bath (approximately 0.5%) until it has recovered. Ulcers should be cleaned in this manner only once as repeated treatments simply inhibit healing by David graham. Conclusion There is much potential for the ornamental fish industry to play an important role in helping to implement these recommendations, particularly in relation to public awareness of the risks associated with the release of ornamental fish into the wild. Considerable research and surveillance and monitoring of diseases and parasites of ornamental fish are needed and this will require adequate funding to achieve. A review of the disease agents recorded in the scientific literature from a short list of some species that have established in India was undertaken with the aim of identifying; their potential for introduction of significant disease agents, gaps in the knowledge of their diseases, criteria for prioritizing which species represent the biggest threat, and to detail practical approaches towards filling in knowledge gaps and mitigating threats posed by these species. References Chao, N.L., P. Petry, G. Prang, L. Sonneschien, and M. Tlusty. 2001. Conservation and Management of Ornamental Fish Resources of the Rio Negro Basin, Amazonia, Brazil-Project Piaba. Manaus, BR: Editora da Universidade do Amazonas (EDUA).
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