Make sure to check your moss balls: Invasive zebra mussels hitch a ride to Wisconsin inside popular aquarium plant

Officials are asking aquarium owners to make sure an invasive species of mussels didn’t hitch a ride into Wisconsin via balls of moss sold at pet stores. 

Zebra mussels have been found within moss balls sold at pet stores across 21 states — including Wisconsin and Michigan, according to the U.S. Geological Survey. The tiny black and white mussels, about the size of a fingernail, were found in moss balls imported from Ukraine on March 2.

Moss balls, popular aquarium plants, are made up of Marimo moss, a form of algae found in Northern Europe and Asia. The algae is popular because of its ability to generate oxygen and remove nitrates from tanks, according to the Michigan Department of Natural Resources. 

A moss ball with a zebra mussel infestation.

The moss balls were sold at stores including Petco and PetSmart.

Even though the moss balls are most often a part of an indoor home aquarium, if an owner improperly disposed of one, zebra mussels could easily get into the environment. 

“The issue is that somebody who purchased the moss ball and then disposed of them could end up introducing zebra mussels into an environment where they weren’t present before,” USGS fisheries biologist Wesley Daniel said in a statement. “We’ve been working with many agencies on boat inspections and gear inspections, but this was not a pathway we’d been aware of until now.” 

The USGS recommends anyone who discovers zebra mussels within a moss ball remove it from their aquarium and either freeze it for 24 hours, place it in boiling water for at least one minute, put it in undiluted chlorine bleach or submerge it in undiluted white vinegar for at least 20 minutes to kill off the mussels. 

The Michigan DNR said there is evidence people have been dumping aquariums into waterways because goldfish and other aquarium species have been found in them.  Employees warned against doing so with any aquariums including moss balls, to ensure the zebra mussels aren’t able to add to the current infestation facing Michigan and Wisconsin. 

RELATED:How invasive species changed the Great Lakes forever

Zebra mussels originated in the Caspian and Black seas regions and are famous for their ability to glue themselves to any hard surface in clusters. They were found in the Great Lakes in the late 1980s, likely having traveled over in freighter ballast tanks.

The small mussels spelled disaster for the Great Lakes, not only because they filtered essential plankton from the water at highly efficient rates, but also because of their ability to clog industrial water intake pipes with ease. Though the mussels may make water cleaner, they leave behind little subsistence for native species in state waters. 

Since infesting the Great Lakes, zebra mussels have infested hundreds of lakes and rivers across Wisconsin, according to the Wisconsin DNR

The USGS is currently studying ways to remove the mussels from the environment, with methods such as low-dose copper applications, carbon dioxide and microparticle delivery of toxicants. 

Laura Schulte can be reached at leschulte@jrn.com and on Twitter at @SchulteLaura