Common Disease Prevention and Treatment Methods and Key Technical Points for Fish and Crabs

I. Grass carp hemorrhagic disease

Symptoms: bleeding in the fins, mouth cavity, eye sockets, muscles, and intestines, partially or entirely bright red.

Prevention and treatment: 1. Broadcast dibromohydantoin or chlorine dioxide over the entire pond, using 200 grams of dibromohydantoin or chlorine dioxide per 1 mu of water surface at a depth of 1 m. Apply once more after 2-3 days. 2. Mix into bait and feed Yu'erkang, mixing 1 kg of Yu'erkang per 50 kg of feed, and feed continuously for three days. 3. Mix into bait and feed Suke, mixing 50 grams of Suke per 50 kg of feed, feeding once a day for three days as one treatment course. If combined with external application of dibromohydantoin and chlorine dioxide, the effect will be even more pronounced.

II. Fish bacterial gill rot

Symptoms: the gill filaments rot and carry sludge; in severe cases the gill filament cartilage is exposed, and the inner epidermis of the gill cover is corroded, forming a transparent "small window" (commonly known as open skylight).

Prevention and treatment: 1. Broadcast dibromohydantoin or chlorine dioxide over the entire pond, using 200 grams of dibromohydantoin or chlorine dioxide per 1 mu of water surface at a depth of 1 m. 2. Broadcast Yuxia Junbijing over the entire pond, using 200-300 grams per 1 mu of water surface at a depth of 1 m. Apply once a day, for two consecutive applications.

III. Fish enteritis

Symptoms: the anus of the diseased fish is red, swollen, and protruding, there are red spots on the abdomen, and the fish loses its appetite shortly after the onset of the disease.

Prevention and treatment: 1. Mix into bait and feed garlic paste, mixing 50 grams of garlic per 500 grams of feed, feeding once a day for 3 consecutive days. 2. Mix 0.1 grams of oxytetracycline per 1 kg of feed and feed, once a day for 3 consecutive days.

IV. Fish skin rot disease (red skin disease, print disease, white skin disease)

Red skin disease symptoms: the fish body surface bleeds and becomes inflamed, scales fall off, most obvious on both sides of the fish body and the abdomen, the fin bases are congested, the fin tips rot and are incomplete, and the fin rays split.

Print disease symptoms: round red spots appear on both sides near the anal pore of the diseased fish, resembling a red seal, with congestion and inflammation around them.

White skin disease symptoms: in the early stage of the disease, there is a white spot at the caudal peduncle of the fish; as the disease progresses, the white spot can spread to the entire skin between the dorsal fin and the caudal fin; in severe cases the caudal fin rots off, the fish hangs head-down vertically in the water, and soon dies.

Prevention and treatment: broadcast dibromohydantoin or chlorine dioxide over the entire pond, using 200 grams of dibromohydantoin or chlorine dioxide per 1 mu of water surface at a depth of 1 m.

V. River crab tremor disease (ring claw disease)

Symptoms: the diseased crab's appendages curl around, it stands unsteadily, moves weakly, has difficulty turning over, and its whole body trembles continuously; it then stops eating, accumulates fluid in the body, and dies.

Prevention and treatment: broadcast dibromohydantoin or chlorine dioxide over the entire pond, using 200 grams of dibromohydantoin or chlorine dioxide per 1 mu of water surface at a depth of 1 m, for 2-4 treatment courses.

VI. River crab ciliate disease

Symptoms: many brown or yellow-green fine hairs attach to the body surface and gills of the diseased crab; the parasite bodies can be found under microscopic examination.

Prevention and treatment: broadcast Xianchong Shaxing, Xiaxie Shachongjing and other drugs over the entire pond, broadcasting 250 grams of Xianchong Kexing or Xiaxie Shachongjing per 1 mu of water surface at a depth of 1 m.

VII. River crab enteritis

Symptoms: the diseased crab has poor digestion, gastrointestinal inflammation, and bloating; when the abdominal flap is opened and the anus is gently pressed, yellow mucus can be seen flowing out.

Prevention and treatment: 1. Add 50 grams of garlic per 500 grams of feed, once a day for 3 consecutive days. 2. Add 0.1 grams of oxytetracycline per 1 kg of feed, once a day for 3 consecutive days.