Velvet disease (also called gold-dust, rust and coral disease) is a fish disease caused by dinoflagellate parasites of the generaAmyloodinium in marine fish, and Oodinium in freshwater fish. The disease gives infected organisms a dusty, brownish-gold color. The disease occurs most commonly in tropical fish, and to a lesser extent, marine aquaria.[1] Periodic use of preventive treatments like aquarium salt can further deter parasites. Regular monitoring, attentive care, and preventive measures collectively contribute to keeping fish healthy and velvet-free.
The single-celled parasite's life cycle can be divided into three major phases. First, as a tomont, the parasite rests at the water's floor and divides into as many as 256 tomites. Second, these juvenile, motile tomites swim about in search of a fish host, meanwhile using photosynthesis to grow, and to fuel their search. Finally, the adolescent tomite[check spelling] finds and enters the slime coat of a host fish, dissolving and consuming the host's cells, and needing only three days to reach full maturity before detaching to become a tomont once more.[2]
Velvet (in an aquarium environment) is usually spread by contaminated tanks, fish, and tools (such as nets or testing supplies). There are also rare reports of frozen live foods (such as bloodworms) containing dormant forms of the species. Frequently, however, the parasite is endemic to a fish, and only causes a noticeable "outbreak" after the fish's immune system is compromised for some other reason. The disease is highly contagious and can prove fatal to fish.
Initially, infected fish are known to "flash", or sporadically dart from one end of an aquarium to another, scratching against objects in order to relieve their discomfort. They will also "clamp" their fins very close to their body, and exhibit lethargy. If untreated, a 'dusting' of particles (which are in fact the parasites) will be seen all over the infected fish, ranging in color from brown to gold to green. In the most advanced stages, fish will have difficulty respiring, will often refuse food, and will eventually die of hypoxia due to necrosis of their gill tissue.[3]
Treatmentedit
Sodium chloride (table/sea salt) is believed to mitigate the reproduction of velvet in freshwater fish, however this treatment is not itself sufficient for the complete eradication of an outbreak. Additionally, one of the common medications designed to combat the disease must be added directly to the fish's environment. These medications usually include the active ingredients copper sulfate, methylene blue, formalin, malachite green or acriflavin. Additionally, because velvet parasites derive a portion of their energy from photosynthesis, leaving a tank in total darkness for seven days provides a helpful supplement to chemical curatives. Finally, some enthusiasts recommend raising the water temperature of an infected fish's environment, in order to quicken the life cycle (and subsequent death) of velvet parasites; however this tactic is not practical for all fish, and may induce immunocompromising stress.[4]
^. The Merck Veterinary Manual. Archived from the original on 3 March 2016. Retrieved 14 September 2017. One of the most serious health problems of captive marine fish is the parasitic dinoflagellate Amyloodinium spp. Its freshwater counterpart, Oodinium spp, is less common but can also result in high mortality. These parasites produce a disease that has been called "velvet," "rust," "gold-dust," and "coral disease" because of the brownish gold color they impart to infected fish. The pathogenic stages of the organism are pigmented, photosynthetic, nonflagellated, nonmotile algae that attach to and invade the skin and gills during their parasitic existence. When mature, these parasites give rise to cysts that contain numerous flagellated, small, free-swimming stages that can initiate new infections
^Kent, Michael L; Fournie, John W (2007). "Parasites of Fishes: Protozoa: Phylum Dinoflagellata". In Baker, David G (ed.). Flynn's Parasites of Laboratory Animals. Blackwell Publishing. pp. 70–72. ISBN978-0-470-34417-0. Retrieved 2024-04-11.
^"Shedding Light on Velvet Disease". Federation of British Aquatic Societies. 2005. Retrieved 2011-05-01.
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Velvet disease also called gold dust rust and coral disease is a fish disease caused by dinoflagellate parasites of the genera Amyloodinium in marine fish and Oodinium in freshwater fish The disease gives infected organisms a dusty brownish gold color The disease occurs most commonly in tropical fish and to a lesser extent marine aquaria 1 Periodic use of preventive treatments like aquarium salt can further deter parasites Regular monitoring attentive care and preventive measures collectively contribute to keeping fish healthy and velvet free Oodinium a genus of parasitic dinoflagellates causes velvet disease in fish Contents 1 Life cycle 2 Pathology 3 Symptoms 4 Treatment 5 See also 6 ReferencesLife cycle editThe single celled parasite s life cycle can be divided into three major phases First as a tomont the parasite rests at the water s floor and divides into as many as 256 tomites Second these juvenile motile tomites swim about in search of a fish host meanwhile using photosynthesis to grow and to fuel their search Finally the adolescent tomite check spelling finds and enters the slime coat of a host fish dissolving and consuming the host s cells and needing only three days to reach full maturity before detaching to become a tomont once more 2 Pathology edit nbsp A 15 day old Siamese fighting fish Betta splendens with velvet disease Velvet in an aquarium environment is usually spread by contaminated tanks fish and tools such as nets or testing supplies There are also rare reports of frozen live foods such as bloodworms containing dormant forms of the species Frequently however the parasite is endemic to a fish and only causes a noticeable outbreak after the fish s immune system is compromised for some other reason The disease is highly contagious and can prove fatal to fish Symptoms edit nbsp Adult Siamese fighting fish Betta splendens with velvet disease Initially infected fish are known to flash or sporadically dart from one end of an aquarium to another scratching against objects in order to relieve their discomfort They will also clamp their fins very close to their body and exhibit lethargy If untreated a dusting of particles which are in fact the parasites will be seen all over the infected fish ranging in color from brown to gold to green In the most advanced stages fish will have difficulty respiring will often refuse food and will eventually die of hypoxia due to necrosis of their gill tissue 3 Treatment editSodium chloride table sea salt is believed to mitigate the reproduction of velvet in freshwater fish however this treatment is not itself sufficient for the complete eradication of an outbreak Additionally one of the common medications designed to combat the disease must be added directly to the fish s environment These medications usually include the active ingredients copper sulfate methylene blue formalin malachite green or acriflavin Additionally because velvet parasites derive a portion of their energy from photosynthesis leaving a tank in total darkness for seven days provides a helpful supplement to chemical curatives Finally some enthusiasts recommend raising the water temperature of an infected fish s environment in order to quicken the life cycle and subsequent death of velvet parasites however this tactic is not practical for all fish and may induce immunocompromising stress 4 See also editPfiesteria piscicidaReferences edit Protozoa Infecting Gills and Skin The Merck Veterinary Manual Archived from the original on 3 March 2016 Retrieved 14 September 2017 One of the most serious health problems of captive marine fish is the parasitic dinoflagellate Amyloodinium spp Its freshwater counterpart Oodinium spp is less common but can also result in high mortality These parasites produce a disease that has been called velvet rust gold dust and coral disease because of the brownish gold color they impart to infected fish The pathogenic stages of the organism are pigmented photosynthetic nonflagellated nonmotile algae that attach to and invade the skin and gills during their parasitic existence When mature these parasites give rise to cysts that contain numerous flagellated small free swimming stages that can initiate new infections Kent Michael L Fournie John W 2007 Parasites of Fishes Protozoa Phylum Dinoflagellata In Baker David G ed Flynn s Parasites of Laboratory Animals Blackwell Publishing pp 70 72 ISBN 978 0 470 34417 0 Retrieved 2024 04 11 Shedding Light on Velvet Disease Federation of British Aquatic Societies 2005 Retrieved 2011 05 01 Freshwater Velvet Piscinoodinium pillulare amp Costia Aquarium and Pond Answers 2007 Retrieved 2011 05 01 Retrieved from https en wikipedia org w index php title Velvet fish disease amp oldid 1222726285, wikipedia, wiki, book, books, library,
