By:S h a r a f a t A l iBS Zool F13 E-23

Ve lve t D i sease(Gold Dust Disease)

Conten tOverview ----------------------------- 03Taxonomy ----------------------------- 04Origin ------------------------------- 05Physiology --------------------------- 06Causes ------------------------------- 07Symptoms ----------------------------- 08

In severe case ----------------------------- 09Biological Cycle --------------------- 10Treatment ---------------------------- 11Prevention --------------------------- 12References --------------------------- 13

OverviewNames: Rust, Gold Dust Disease,

Oödinium, VelvetDisease Type: Parasitic skin flagellateCause / Organism: Oödinium pilularis

TaxonomySuper class :  Dinoflagellata Class :  Dinophyceae Order :  Peridiniales Family :  Oodiniaceae Genus :  OodiniumSpecies :

Oodinium limneticumOodinium pillularisOodinium pouchetii

5

OriginThe most common type of fish prone to this

disease is the dinoflagellateOodinium pillularis species, discovered by Schaperclaus in 1951. The oodinium is round or oval in shape (pear-shaped).

Geographical DistributionFreshwaterMarineBrackish

Location in hostAttached to epithelial tissues of the skin,

fins, and gills.

Biological Cycle of the Parasite

CausesAbrupt changes in water temperatureIntroduction of new fish without quarantineTired fired that are lacking in defensesOld water—you should be frequently

changing your water.Introduction of plants with cysts (if bringing

in new plans, make sure to disinfect prior to their introduction)

SymptomsDuring the beginning of the infection, the

affected fish will show some behavioral changes, like fin twitching or body rubbing.

As it advances, the skin of the sick fish becomes dusty and opaque due to the excess of mucus that their immune system generates as a defense mechanism.

Since the parasite affects the gills, it is common that respiratory failure appears.

Physiology

In Severe caseExophthalmiaFins against the bodyUlcers in the skinSkin detachmentExophthalmiaLoss of appetite and weight lossRapid, labored breathingFins clamped against bodyFine yellow or rusty colored film on skinIn advanced stages, skin peels off

Treatment Quinine salts or methylene blue Raise water temperature Dim lights for several days Some species of the parasite also obtain energy through

photosynthesis. Try to cover the aquarium, which can lend to the weakening of the parasite.

Increasing the temperature of the water can also help with treatment because the parasite's life cycle is accelerated through the heat.

Salt baths are an ineffective cure for a sick goldfish with velvet disease; an ionic copper treatment, a free-form copper (chelated), is effective.

Formalin is also an effective treatment for velvet disease. It too needs to be used with care to avoid burning the fins of the goldfish.

PreventionThe parasite can be latent, waiting for a favorable

condition. When the fish are weakened, the disease then attacks. When the fish are stressed, they weaken.

Stress can also be due to poor maintenance conditions of the water or abrupt changes of temperature when making the water replacements.

Parasite cysts can also enter through sick new fish or through infected objects. To further prevent this, make sure you quarantine any new fish or objects and ensure hygiene before introducing them to the tank.

References Papperna I. (1980) Amyloodinium ocellatum (Brown 1931) (Dinoflagellida)

infestations in cultured marine fishes in Eilat , Red Sea: epizootiology and pathology J.Fish Dis 3: 363-372

Noga E. (1987) Propagation in cell culture of the dinoflagellate Amyloodinium , an ectoparasite of marine fishes Science 236. 1302-1305.

Cheung P.J., Ruggieri G.D., and Nigrelli R.F. (1978) Effects of temperature & salinity on the developmental cycle of Oodinium ocellatum Brown (Mastigophore: Phytomastogophoresa: Dinoflagellida)(abstract) The Fourth International Congress of Parasitology in Poland.

Negrelli R.F. (1936) The morphology, cytology, and life-history of Oodinium ocellatum, a dinoflagellate parasite on marine fishes. Zool N.Y. 21: 129-164.

GÓMEZ F (2005). "A list of free-living dinoflagellate species in the world's oceans". Acta Botanica Croatica. 64 (1): 129–212.

Sindermann, C.J. 1970. Principle Diseases of Marine Fish and Shellfish. Acad. Press, N.Y. pp. 6, 228, 231

Noga, Edward J. 1996. Fish Disease, Diagnosis and Treatment. Mosby-Year Book Inc., St. Louis. 367pp.

Jacobs, D. L. 1946. A new parasitic dinoflagellate from freshwater fish. Trans. Am. Micr. Soc. 65:1-17