High mortality of rainbow tour (Oncorhychus mykiss) fingerlings, affected by Ichthyophthirius multifiliis in Golbahar

Objective: The parasites are one of the serious problems in many of the aquarium, cold and warm water fields. One of these parasites is known as Ichthyophthirius multifiliis which replaces in the hypoderm of fish's body, so its treatment becomes harder than usual. This parasite has no specific host and tends to affect the young fishes. Ichthyophthirius multifiliis infects gill, skin and fins and begin to reproduce very fast, so that white spots can be observed shortly after infection, specially in the advance stage of the disease, so it is called as White Spot Disease. Method & Materials: There was high mortality of rainbow trout fingerlings (3-5 gr) in Golbahar`s farm. The symptoms were as following: White tiny spots on dorsal, pectoral and caudal fins root with high mucosal secretion on their body surface – hyperpnoea - anorexia and the fish accumulation in the entrance of water through the pool. To diagnose this disease in the laboratory, many of Ichthyophthirius multifiliis were observed in the zone wet preparation so it results in the sign of intensive parasite contamination in the farm. Results & Conclusion: Putting rock salt in the entrance of water of the pool caused reduction in parasite number but it did not decrease the number of dead fishes. At the end, NaCl solution bath used inevitability and after two weeks we got a successful result. The farm became quite clean from this dangerous parasite. Above all of this we recommend the managers to be quite sure of their fish's health before entering them to the pool or keep them in quarantine for more security, and after parasite and microbial test they throw their fishes to the pool.

کلیدواژه ها:

fingerling ، rainbow trout ، Oncorhychus mykiss ، Ichthyophthirius multifiliis