A photo of a redfin covered in the unpleasant spots taken at the Burrendong Classic at Easter has been circulating on Facebook.

Senior NSW DPI Fisheries manager Samantha Davis posted a photo from the Burrendong Classic on Facebook of a redfin affected by the disease. 

It had attracted 3380 shares and 393 likes by Tuesday, with 560 people commenting. Some suggested it was carp herpes virus but Ms Davis said carp herpes hadn’t been released in Australia yet and only affects carp.

Mr Hansen said he understood the virus was dermatological and appeared to be only affecting redfin, leaving native fish unharmed.

“I don’t think there is any reason for alarm. It will be interesting to see what it is,” Mr Hansen said.

“It was noticed at the Burrendong Classic. A number of people caught redfin that were covered in it. We alerted local fisheries who started to investigate and asked for a sample.

“We had 1300 anglers at the Burrendong Classic and while there were a lot of redfin with the spots, none of the natives that were caught showed any signs of it, so that’s good news.

“It could be EHN virus, which redfin do get and it is dermatological, or it could be related to water quality.

On Monday Ms Davis updated her post to say a redfin sample had been provided and was going to be couriered a biosecurity lab and an analysis done.

Redfin, also known as English perch, are a class 1 noxious pest in NSW, Mr Hansen said.

“They can get a real stranglehold. A group of us went to Carcoar on Sunday and we caught 342 of them and just one native cod so they are an absolute pest,” he said.

There were also no alerts from NSW fisheries warning against eating the fish, Mr Hansen said.