Zebra mussels have hitch-hiked their way to Alaska via a very unlikely suspect: MOSS BALLS! While Zebra mussels are widely known to hitch-hike rides on boat motors, in ballast water, and on other aquatic recreation equipment, this is a new and hazardous vector for this highly invasive species.
If you have found a Zebra mussel infested moss ball within your own aquarium, report it directly by calling 1-877-INVASIV (1-877-468-2748) or report online, and document with photos before destroying.


Zebra mussels have been wreaking havoc in areas where they have infested lakes and rivers in the lower 48 since the 1980s when they were first discovered to have traveled to North America via ship ballast water. These mollusks are filters feeders that can greatly alter water chemistry, degrading habitat for fish and other native species. They pose an immense threat to recreation and infrastructure, as they damage boats, clog pipelines used for water filtration, and litter beaches with sharp shells that are a direct threat to human health.
The Kenai Peninsula has already been subject to several novel infestations of aquatic non-native species (i.e. northern pike and elodea). If an infestation of Zebra mussels were to take hold within the waters of the Kenai Peninsula, it would quickly become impossible to stop their spread. Habitat destruction would be imminent and the recreation industry would suffer greatly. Millions of tax-payer dollars would be needed to prevent serious damage to the commercial and sports fishing industry.
So what role do the moss balls play in all of this??
Moss balls are popular additions to home/office aquariums as well as outdoor ponds and aquatic gardens. While they look like moss, they are actually an algae that is easy to maintain in aquarium settings and provides habitat for fish, shrimp, and other species (like Zebra mussels). They are sold through popular pet/aquarium supply chains in every US state, including major online markets. Moss balls themselves are not known to be invasive in North America, but this vector has given Zebra mussels the ability to quickly reach more than 30 US states, many of which have not yet had Zebra mussels breach their borders. If you recently purchased moss balls, follow these instructions to Destroy! Don’t Dump! The source of the Zebra mussel infested moss balls is not yet known: contamination could be happening within supply, distribution, or retail chains.
While the widescale distribution of Zebra mussels through moss balls is a new and scary prospect, this is not the Kenai Peninsula’s first aquarium scare.
Elodea, Alaska’s only known aquatic invasive plant, is a popular aquarium addition. All original infestations of Elodea in Alaska can be closely traced to an illegal dumping of an aquarium into a freshwater body. Elodea eradication efforts on the Kenai Peninsula alone have cost hundreds of thousands of dollars in the past 10 years. Thankfully, our eradication efforts have been successful thanks to collaborative efforts between state and federal agencies, non-profits and local goverments.


To prevent Zebra mussels from escaping aquariums and infesting Alaska’s freshwater systems, state and federal officials are asking anyone who has purchased these moss balls within the past several months to DESTROY the moss balls as soon as possible (Zebra mussels do NOT make good house pests, trust us…).
The USFWS has issued the following guidance on how to destroy these moss balls: Carefully follow these steps to Destroy! Don’t Dump!
- (1st) DESTROY moss balls in one of three ways: freezing (24 hours), bleaching (20 minutes), or boiling (1 full minute)
- (2nd) DISPOSE of moss balls in a sealed plastic bag, in the trash
- (3rd) DECONTAMINATE and properly DRAIN your aquarium, sanitize all contents
When cleaning ANY aquarium, decontaminate or sanitize water (1/2 cup salt per gallon of water; or 1 cup bleach/gal. water) before pouring down the drain. Drain decontaminated water down household drains only. Remember, it is ILLEGAL to dump aquarium contents into stormwater drains or into the wild.
If you have found a Zebra mussel infested moss ball within your own aquarium, report it directly by calling 1-877-INVASIV (1-877-468-2748) and document with photos before destroying.
The KP-CISMA is hopeful that the Early Detection and Rapid Response methods being taken by our Federal and State partners, coupled with responsible aquarium owners, will be effective in preventing Zebra mussels from accessing Alaskan waters.