Officials Say Invasive Zebra Mussels Are Hiding in Aquarium Decor Sold Across U.S.

Pet stores in 21 states recall items after reports of the destructive bivalves lurking in moss balls

zebra mussel on moss ball
A tiny, invasive zebra mussel found on a moss ball sold as aquarium decor in a pet store. Officials say moss balls containing the invasive species have been reported in pet stores in at least 21 states. USGS

Federal officials in the United States warn that invasive zebra mussels have been discovered lurking in shipments of moss balls sold as aquarium accessories in pet shops across the country, according to a statement from the United States Geological Survey (USGS). The statement says the invasive freshwater bivalves, which are native to Eurasia, have been found in pet shops in at least 21 states.

The Conservation Officer Service in British Columbia, Canada, has also reported finding zebra mussels in pet shops after conducting searches at some 600 locations, reports David Carrigg of the Vancouver Sun.

Zebra mussels are tiny, about the size of a fingernail, but they can be incredibly destructive. According to USFWS, when these small, stripey mollusks “become established in an environment, they alter food webs and change water chemistry, harming native fish plants and other aquatic life. They clog pipelines used for water filtration, render beaches unusable, and damage boats.”

Zebra mussels can quickly establish themselves and multiply if they are introduced to a water source, even if they are flushed down a toilet. In the Great Lakes region, for example, dealing with invasive Zebra and quagga mussels costs hundreds of millions of dollars every year, reports the Associated Press.

USGS officials tell the Detroit News' Mark Hicks that all moss balls should be treated as though they contain zebra mussels and destroyed before being properly disposed of in a sealed container in the trash. The U.S. Fish and Wildlife Service (USFWS) recommends destroying the hardy mussels by freezing, boiling or bleaching any moss ball or other item suspected of containing the invasive species.

The first sighting of zebra mussels in the moss balls was reported by a PetCo employee in Seattle, Washington, on February 25, according to the AP. After notifying local officials, USGS fisheries biologist Wesley Daniel took a trip to a pet store in Florida only to discover a zebra mussel in a moss ball there too, suggesting the issue was widespread. Since then, reports have come in from Alaska, California, Colorado, Florida, Georgia, Iowa, Massachusetts, Michigan, Montana, Nebraska, Nevada, New Mexico, North Dakota, Oklahoma, Oregon, Tennessee, Vermont, Virginia, Wisconsin, Washington and Wyoming, per USGS.

In a statement emailed to Newsweek's Jason Murdock, a Petco spokesperson says the company has “immediately paused the sale of all Marimo aquarium moss balls at Petco locations and on petco.com.”

The geographic extent of the moss balls, specifically “Betta Buddy” branded marimo balls, has experts concerned the incident could spread the mussels to new areas.

"This is one of the most alarming things I’ve been involved with in over a decade of working with invasive species," Justin Bush, executive coordinator for the Washington Invasive Species Council, tells local broadcast network KING 5.

A bit farther south, Rick Boatner, the invasive species wildlife integrity supervisor at the Oregon Department of Fish and Wildlife, tells Bradley W. Parks of Oregon Public Broadcasting (OPB) that a zebra mussel infestation “would be devastating to our environment if these ever got established in Oregon or the Pacific Northwest.”

Per OPB, the Pacific Northwest has been able to mostly keep zebra mussels at bay through strict monitoring of boats and other craft, which are one of the primary vectors for introducing the mussels to new waters.

However, Boatner admits to OPB, his agency was “not expecting zebra mussels from moss balls.”