Home aquarium moss balls may be contaminated

The Virginia Department of Wildlife Resources (DWR) issued a warning to anyone who has recently purchased live marimo moss balls, which may be contaminated with invasive zebra mussels.

The moss balls are commonly sold for aquarium use under trade names such as “Betta Buddy” and “Mini Marimo Moss Balls.” This product was sold through physical pet stores and online retail outlets. Contaminated moss balls have been confirmed at several stores in Virginia.

Marimo moss balls are a species of algae that forms a ball two to five inches in diameter and is commonly purchased to place in home aquariums to improve water quality and aesthetic appeal. Zebra mussels are small, D-shaped, thumbnail sized or smaller and have a white and black striped pattern. Even if no zebra mussels are visible on the moss balls, they could be contaminated by young individuals that are not visible to the naked eye.

Zebra mussel invasions have caused tremendous economic and ecological damage. Zebra mussel populations are extremely difficult to eradicate, and once established, require significant yearly maintenance costs to maintain infrastructure for power generation or water supply. Currently, there are no zebra mussel population in Virginia, but they are present in adjacent states such as West Virginia and Maryland. Additional information on zebra mussels can be found at the Department’s website at

Consumers who have recently purchased marimo moss balls should dispose of them immediately by placing them in a plastic bag and freezing them overnight, boiling them or soaking them overnight in a bleach solution (one cup of bleach per gallon of water). The moss balls should then be bagged and disposed of in the trash. Aquariums should be cleaned by first removing the fish, adding bleach, and then disposing of the water down the sink or toilet.

Under no circumstance should moss balls, or any aquarium species, be released into the environment. Penalties for the unlawful act of releasing zebra mussels, which are known to be associated with these moss balls, may reach $25,000 and may include additional fines for investigation and eradication.

Retailers are in the process of pulling the moss balls off the shelf. This product was imported from Ukraine to a distributor in California and then shipped nationwide. The distribution facility is under quarantine and all shipments have stopped, according to a news release from Montana Fish, Wildlife, and Parks. Some products may still be on the shelf, and consumers should not purchase marimo moss balls until further notice.

Anyone who has purchased this product and found zebra mussels is asked to alert the DWR at



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