PUEBLO, Colo. (KDVR) — If you plan to go fishing anytime soon, Colorado wildlife officials are asking you to keep an eye on your catch. 

“Last fall we had an angler contact us about a fish that had unusual granular stuff in its fillets,” Colorado Parks and Wildlife aquatic biologist Carrie Tucker said. 

According to Tucker, the fish was suffering from “sandy flesh disease.” It was taken from Lake Pueblo. This is the first time a case has been documented in Colorado. 

“It is a little bit of a surprise, especially since we don’t know what causes this disease but at the same time with people being very mobile and moving all over the country and fishing other states and coming back it’s not a surprise that it eventually made its way here,” Tucker said. 

While there have been a few cases in Utah, Kansas and Nebraska, the disease is considered rare. 

“We don’t expect many people to find this disease so I just want to stress this is nothing to be alarmed about,” Tucker said. 

Tucker said almost every documented case of sandy flesh disease has been in older walleye.

“Typically there’s no external signs that there’s anything wrong with the fish so people won’t know if the fish is infected until they start filleting the fish,” Tucker said. “It kind of looks like, as the name implies, sand in the fish fillets and it’s just little tiny globules all lumped together kind of like knotty muscle tissue.”

She says the aquatic disease is similar to muscular dystrophy in humans. However, CPW does not believe sandy flesh disease is transmissible to humans. 

“We’re just trying to get an idea of the prevalence in Colorado. We don’t expect it to affect very many fish at all,” Tucker said. 

If an angler believes he or she has caught a fish infected with sandy flesh disease, CPW says they should take photographs to document the visible signs of the illness and to contact the local CPW office. 

Do not eat infected fish. Do not throw infected fish back into the water. Infected fish should be thrown away into a trash can or buried.