Keep your moss balls out of Yukon, N.W.T. waterways Fisheries authorities want Northerners to beware of purchasing moss balls, which can introduce invasive mussel species that would harm waterways and species like salmon. Social Sharing CBC News · Posted: Mar 12, 2021 4:24 PM CT | Last Updated: March 12 A B.C. Conservation Officer Service tweeted a picture of one of the invasive species recently found on popular aquarium plants known as moss balls, originally shipped from pet suppliers in Europe.(B.C. Conservation Officer Service)