What is whirling disease?
“Whirling disease” is a disease of salmonid fish, the family of fish that includes trout, salmon, and whitefish. The disease is caused by a microscopic parasite known as Myxobolus cerebralis. In an infected fish, the parasite can affect nerves and cause cartilage damage which results in the outward signs of whirling disease. Whirling disease gets its name from the abnormal whirling or tail-chasing behavior exhibited by some infected fish. Other symptoms may include a black tail in younger fish. In older fish, signs may include deformities to the head or body. Severe whirling disease infections can kill fish. Carriers with no visible signs of disease are common.
