Etiological Symptoms Of Eel

During the high temperature period in summer, the eel is overfed, the sewage is not completely discharged, and the organic debris in the pond decays; Rainstorm causes water source change; Frequent use of highly irritant insecticides to kill insects and so on is the latent factor that causes the gill disease of eels, while parasites cause the gap of gill filaments, which is very easy to cause the breeding of pathogenic microorganisms, and ultimately lead to the outbreak of gill disease of eels.
The eel farms are different and the eel species are different (refer to Japanese eel and European eel), but the symptoms of the diseased eel are basically the same: the body surface of the diseased eel shows black and white mottled annular stripes, and some seriously diseased eels have congested and red pectoral fins, swollen and protruding anus, gently pressing the gill cap, and yellow pus flowing out; Anatomy of internal organs, liver whitening (some related to medication), gallbladder enlargement, empty stomach and intestines, and the outer wall covered with blood, and serious abdominal cavity filled with blood and water; When the gill cover is cut off, the gill filaments of most diseased eels show white and white stripes. The second or third gill filaments have a large defect, and a layer of mud and other dirt is attached to the wound of the defective gill filaments. Scrape off the dirt, cut off the gill filaments at the defect and conduct microscopic examination under the low power microscope. After careful observation, it can be seen that the branchial mold filaments in the form of branching branches are attached to the gills of the diseased eel.
In addition, in some eel farms, due to the incomplete treatment of parasites in the early stage, there may also be rotifer (parasitism on the body surface) or ringworm infection on the gill filament.