Fish Hatchery Management - fisheries & aquaculture

FISH HEALTH MANAGEMENT 321Trichodina on warmwater fish can be controlled with any of the followingtreatments:(t) Copper sulfate as an indefinite pond treatment at whatever concentrationcan be used safely in the existing water chemistry.(2) Potassium permanganate at 2 parts per million as an indefinite pondtreatment.(3) Formalln at l5-25 parts per million as an indefinite pond treatment.(4) Formalin at 125-250 parts per million, depending on water temperatureand species and size of fish, for up to I hour.To control Trichodina on salmonids, formalin at 167-250 parts per millionfor up to I hour usually is successful. If salmonids are sensitive to formalin,a 2-4 parts per million treatment of Diquat for one hour should betested.AMBIPHRTAAmbiphrya (Scyphidia) can occur in large numbers on the skin, fins, andgills of freshwater fish.The organism has a barrel-shaped body with a band of cilia around theunattached end and around the middle of the body, and a ribbon-shaPed14,'i!! ,l:FrcuRE 92. Episttlis, l00x magnification. (courtesy G. H. Hoffman, Fish FarmingExperimental Station, Stuttgart, Arkansas..)