Zebra Mussel FAQ
What are Zebra Mussels and what is the issue? Zebra Mussels are a freshwater mussel native to the lakes of southern Russia and Ukraine. They were introduced into the US in the 1980s and have already caused signifant damage to local ecosystems. Recently, they began appearing in shipments of "moss balls" sold at aquarium stores nationwide, including PetSmart and PetCo. The immediate concern is that they will now spread further and more rapidly to other parts of the country. As of Mar 11, they have been found in pet stores in 22 states (including NC & SC).
The US Fish & Wildlife Agency has issued a statement (and revised it a few times):
Destroy! Don't Dump! - Zebra Mussel Disposal
More info:
SCDNR - Aquatic Nuisance Species Program Dreissena polymorpha/Zebra Mussel
Zebra Mussels: A guide to the good and the bad of these Great Lakes invaders – Great Lakes Now
What do Zebra Mussels look like? They are small animals with a striped, D-shaped shell. Adults are typically fingernail-sized. They attach to hard surfaces underwater.
More info:
zebra mussel (Dreissena polymorpha) - Species Profile
Prevent the Spread of Zebra Mussels | Invasive Species in Lake George
I have moss balls in my tank. What should I do? First, we don't know yet how long the moss ball supply chain has been infected with Zebra Mussels. First discovered in February, 2021, it may well be that they have been for sale in stores for much longer (they have been confirmed to have been found in inventory going back a month). So if you have moss balls that you've received in the last 6-12 months, take them out and inspect them for mussels. Also, inspect your tank for any signs of them.
More info:
I've found them in my tank. What do I do? Unfortunately, if you have them, the only definitive way to get rid of them is to effectively sterilize the tank. In addition to the mussels themselves, there may be eggs and tiny larvae in the tank (too small to see). If you are part of RAS, notify the club that you have them, either by sending a note to the ras@ras.groups.io list or to the board (ras-board@groups.io).
More info:
About zebra mussels | Minnesota Aquatic Invasive Species Research Center (MAISRC)
I have fish in an infected tank. What do I do with them?
Current recommendations state that one can remove the fish with a net (i.e., just the fish, no water) and place in another container in uncontaminated water. Sterilize original tank. Once original tank has been sterilized/cleaned, move fish back. Note: your cleaned tank will effectively be a new tank and have no biological filtration. You will need to reestablish a new filter quickly in order to protect the fish from ammonia poisoning.
The US Fish & Wildlife Service has issued detailed guidance on treating an infected tank:
Destroy! Don't Dump! - Zebra Mussel Disposal
Note: although current recommendations state that fish can be netted out, there is a perhaps low, but non-zero chance that eggs or larvae will attach to the net and hence provide a vector for further contamination.
Reference: PIJAC UPDATE: Zebra Mussel Problem Growing in Scope
I have a new/sterile tank, how do I reestablish a bio filter quickly? A: borrow filter from another tank. Or take new filter media, rub sides of established tank to scrape bacteria onto filter media, then put into new filter. (XXX need to fill out). Fellow RAS members will surely volunteer to help seed your filters if you need help.
References:
I apparently have them in one of my tanks. Are my other tanks safe, or will they be infected too? A: They are at risk of being infected. Unless one practices perfect aquarium room hygiene (and let's face it, who does?) there is a real risk that one tank can infect another tank through dirty hands, unsterilized fish nets, hoses and gravel vacuums, etc.
Can I safely move the fish from a infected tank to a clean one safely? A: this is not enough (need details). May be attached to fish (e.g., gills). Some water will be transfered, the net will be contaminated, etc. Note: need pragmatic guidance here. (and note, this conflicts with previous advice.)
What are pet stores saying about this? (A: not much)
What are government agencies and other organizations saying about this? A: a lot. They are all concerned. They are working on providing more concrete guidance as they determine the extent of the problem and what measures to take.
References:
US Fish and Wildlife: Destroy! Don’t Dump
North Carolina Wildlife Resources Commission: UPDATE to Consumer Alert: Aquarium Moss Balls May Contain Invasive Zebra Mussels
What are various news organizations reporting:
How do I dispose of contaminated moss balls (and other plants):
A: a) Freeze for 24H, b) boil for at least 1 min, c) treat with bleach for 10 minutes (1 cup bleach/gallon water), d) treat with undiluted vinegar for 20 minutes. Seal packaging in plastic bag, then put in trash.
Reference:
How do I dispose of contaminated water? A: see recommendations in:
Where can I report finding a moss ball:
Aren’t Zebra Mussels already in the US? A: Yes, but they are not everywhere and have not been found in North/South Carolina. Let’s keep them out.
References: