Velvet (fish disease)

Source: Wikipedia, the free encyclopedia.
velvet disease
in fish

Velvet disease (also called gold-dust, rust and coral disease) is a

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 Goldfish health
and Velvet-free.

Life cycle

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]

Pathology

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

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

hypoxia due to necrosis of their gill tissue.[3]

Treatment

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

References

  1. 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
  2. ISBN 978-0-470-34417-0
    . Retrieved 2024-04-11.
  3. ^ "Shedding Light on Velvet Disease". Federation of British Aquatic Societies. 2005. Retrieved 2011-05-01.
  4. ^ "Freshwater Velvet – Piscinoodinium pillulare & Costia". Aquarium and Pond Answers. 2007. Retrieved 2011-05-01.
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