Control methods for ciliate disease in mandarin fish aquaculture

Ciliate disease in mandarin fish generally occurs from the first day after hatching until the fish reaches a body length of 5-8 cm. When the water temperature is 20°C-27°C, parasites such as Trichodina are often found on the body surface of mandarin fish. Before the fish reaches 3 cm, they are mostly distributed over the entire body and in the oral cavity; after 3 cm, they concentrate in the oral cavity, gills, fin rays and tail, with the number of parasites showing a decreasing trend; when the water temperature is above 27°C, the number of Chilodonella parasites increases, generally parasitizing the body surface and gills. When the number of ciliates is small, there is little effect on the fish's activity; when the number is large, the fish eats little, and in severe cases refuses to eat. With the naked eye, grayish-white spots can be seen on the head of the diseased fish, the mouth is open and cannot close, the body loses balance and sinks or rolls in the water, and then dies. The disease spreads rapidly; in just one day and night, the number of Trichodina on each fry can increase from a few to 40-50. It is one of the major diseases in the process of rearing mandarin fish summer fry, and is extremely harmful.

Control methods:

1. For flow-through ponds, splash 3% salt water over the entire pond once a day, stopping the water flow for 3-5 minutes, which can have a preventive and therapeutic effect.

2. For flow-through ponds, splash a mixture of 1.6 PPM copper sulfate and ferrous sulfate (5:2) over the entire pond, and stop the water flow for 3-5 minutes, with obvious efficacy; for still-water ponds, splash a mixture of 0.7 PPM copper sulfate and ferrous sulfate (5:2) over the entire pond.

3. When stocking mandarin fish summer fry into the pond, soak the diseased fish in 2% salt water for 2 minutes.