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Type: Ectoparasite, Protozoa(singele celled organisms)

Symptoms:Body and gills of the fish are covered with small yellowish brown spots(In O. pillularis, in O. limneticum the spots are more greyish).

Description: Oodinium pillularis is a flagellate, pearshaped and up to 0.013 mm large.The parasite multiplies in a cyste. The naupllii swim around in the water until they find a host, they will use their pseudopodia to penetrate the skin of the fish, and extract food from the epidermiscells. The parasite will fully grow in a few days, after which it will fall off the fish(pillularis) and reproduce itself in the soil, by forming a cyste. Each cyste will produce 32-64 new dinospores, that will start to swim around, looking for a host. They swim using a pair of flagellae. If a host is found, the spore looses it's flagellae. If no host is found within 24 hours, the spores will die. Oodinium dinospores can use the chlorophyll in their body to fotosynthesise, and survive in a non parasitic form for a long time.

Oodinium limneticus reproduces on the skin of the host. The parasite creates a circlelike cyst on the host, in which reproduction takes place. After reproduction is completed, the cyst will burst open and release hundreds of dinospores.

Infections: Dormant stages of Oodinium can suddenly appear in tanks, if the fish are weakened. Usually it also reappears if fry are present in a tank, and the disease is notorious for it's ability to kill complete batches of fry within a day or two. After a fish has been infected, the disease is very contagious. Stories abour airborne Oodinium are unlikely to be true.

Treatments:

- Saltwatertreatment; dissolve 30-50 grams of salt in 1 liter of water. Place the fish in the water in a net for 1-3 minutes. Remove the fish if signs of weakness occur into a quarantine tank with fresh water.

- Trypaflavine, 1 gram per 100 liter of water. Turn of the light, and raise the temperature to 30 degrees. Leave the fish in the treatment until the disease is cured.

- Kininechloride, 1.5 grams per 100 liter, same as trypaflavine. This treatment has a detrimental effect on plants!

- Methylen blue

Temperature: During all treatment it is advisable to raise the temperature to 30 degrees, if the fish can stand it.

Feeding: The fish can be fed during the treatment, but only small amounts of food that are eaten immediately.

Quarantine period for new fish, and for treated fish: 10 days.

Additional: Latent forms can be present in some fish,

Picture references: No pictures or drawings available at this time.

References:Frey, B&R, Mills&Vevers, Axelrod

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