The Maine Department of Inland Fisheries & Wildlife has issued a warning about highly invasive zebra mussels, which have been found hitchhiking on aquatic moss balls sold in pet stores in Maine. PHOTO COURTESY OF MDIFW

Highly invasive zebra mussels found on aquarium plants 

ELLSWORTH  Zebra mussels, a highly invasive and prolific species, have been found hitchhiking on aquatic moss balls sold in pet stores in Maine and throughout the country. Maine’s natural resource agencies are urging anyone who may have bought these moss balls to destroy them, and for pet stores to remove them from the shelves and destroy them immediately. 

Zebra mussels are fingernail-sized mollusks native to fresh waters in Eurasia. Their name comes from the dark, zig-zagged stripes on their shells. 

Zebra mussels probably arrived in the U.S. in the 1980s via ballast water that was discharged into the Great Lakes by large ships from Europe. They have since spread rapidly throughout many parts of the U.S. but have not yet been found in Maine. State officials say it is essential to prevent them from becoming established in the state. 

Zebra mussels have been found at pet stores in central and southern Maine already, and state agencies say they are likely elsewhere at pet stores throughout the state. If accidentally or intentionally released into the wild, these zebra mussels can quickly outcompete native species, and can clog boat motors, hydropower structures, intake pipes and other in-water structures. 

Zebra mussels have been found on moss balls sold as aquarium plants that have names including “Beta Buddy Marimo Balls,” “Mini Marimo Moss Balls” and “Marimo Moss Ball Plant.” These moss balls are sold separately but are also sometimes included in the sale of betta fish. 

State agencies say that customers who bought these moss balls should destroy and properly dispose of them immediately, then disinfect the container or aquarium they were inBut whatever you do, don’t flush moss balls or untreated water down the toilet or dispose of them anywhere they could get into a water system. 

The Maine Department of Inland Fisheries & Wildlife outlines three methods of destroying moss balls: freeze, boil or bleach. 

To freeze, place the moss ball into a sealable plastic bag and freeze for at least 24 hours. Placing the moss ball in boiling water for at least 1 full minute is another method. Or you can submerge the moss ball in chlorine bleach for 20 minutes. 

If the moss balls were in a fish tank, the entire tank will need to be disinfected, according to MDIFW. 

To do so, remove fish, destroy all aquatic plants in the same manner as the moss ball and add 1 cup of household bleach per gallon of water. Mix well and let sit for at least 10 minutes in the tank. The bleached tank water can then be drained and disposed of down the sink or toilet. 

Thoroughly disinfect (or replace) all gravel, pumps, filters, decorations and other items in the aquarium with a bleach solution (1 cup bleach/gallon of water), letting them soak for at least 10 minutes. 

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