Scott Decker: (603) 271-2501
Jay Martin: (603) 271-3211
March 10, 2021

CONCORD, NH – Zebra mussels, a highly invasive and prolific species of freshwater mollusk, were recently detected in aquatic moss balls sold in pet stores across the United States, but not in New Hampshire. These moss balls are used as ornaments in aquariums.

The U.S. Geological Survey issued an alert when a citizen reported finding a mussel in moss at a pet store and discovered the aquatic invasive species (AIS) in 21 states. The concern is that these mussels could spread to areas where they have not been found before if they are accidentally or intentionally released into the wild. The moss balls are sold separately as aquarium plants as well as included in the sale of betta fish. Pet stores in Maine, Massachusetts, and Vermont have received these infected products.

These fingernail sized bivalves quickly outcompete native species and disrupt the food chain, change water chemistry, and clog water intake and delivery systems for drinking water, irrigation, and hydropower. They can also attach to boats, docks, and fishing equipment and cause enormous damage.

If anyone has bought these moss balls, it is important that they be destroyed and properly disposed of immediately, along with disinfecting the water in any aquarium. DO NOT flush moss balls or untreated water down the toilet or dispose of anywhere they could get into a water system. The moss balls can be destroyed by: freezing—place the moss ball in a sealable plastic bag and freeze for at least 24 hours; boiling—place the moss ball in boiling water for at least 1 full minute; bleaching—submerge the moss ball in chlorine bleach for at least 20 minutes.

For more information, please visit For questions, please reach out to the NH Fish and Game Department, Inland Fisheries Division at 603-271-2501. For more information regarding moss ball product recall, visit and To learn more about zebra mussels, visit