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Guidelines for Aquarium & Pet Owners

If you have purchased a moss ball since March of 2020, it may have contaminated your aquarium with invasive zebra mussels. Find out more about proper disposal.

Protect Our Environment: Be a Responsible Aquarium & Pet Owner

A person holding a large goldfish
Goldfish, a popular aquarium pet, outcompete
native fish in the wild, Photo credit: USGS,

Some invasive species can be purchased in stores that sell exotic pets and plants for aquariums and ornamental water gardens. Occasionally, owners can no longer keep their animals and plants and dispose of them in nearby streams, ponds or lakes, or simply flush them down the toilet. For example, red-eared slider turtles are often sold as juveniles, when they are only about four inches long. This popular species can live for more than 20 years and may triple in size during its lifespan. Pet owners may be unprepared to care for a pet for such a long time and sometimes release the turtle into a local wetland.

Releases may seem safe and even humane, but discarded plants and/or animals can degrade our natural ecosystems. If enjoyed and disposed of properly, however, exotic pets and plants do not pose a threat.

Impacts of Invasive Species

Aquarium fish such as lionfish and goldfish compete with native fish for resources and may even feed on the young of native fish species. Goldfish in particular can tolerate poor water quality and low oxygen levels, enabling them to outcompete native fish in degraded ecosystems. Invasive aquatic plants like hydrilla, fanwort, and Brazilian elodea can vigorously reproduce and overtake waterways, impairing recreational uses such as swimming, fishing and boating. Red-eared slider turtles are opportunistic omnivores and can outcompete native turtle species for food and habitat. They are also known carriers of Salmonella bacteria, which they can pass on to other turtles and to humans who handle them.

How You Can Help

The following best management practices apply to various activities, including but not limited to maintaining a water garden and/or aquarium, purchasing study specimens for classrooms and owning exotic pets:

  • Select species that comply with federal and state regulations, which prohibit or regulate the sale, possession, and transport of certain species.
  • Confirm the scientific name of plants or animals with the retailer to ensure you have the correct species information and proper care instructions.
  • Inspect the contents and packaging that arrive with any plants or animals purchased. Remove unwanted seeds, plants or animals, and put them in a sealed plastic bag for the trash.
    A person holding fanwort, an invasive aquatic plant
    Fanwort, an invasive aquatic plant, is often marketed
    as an oxygenator for freshwater aquariums. Photo
    credit: Graves Lovell, Alabama Dept. of Conservation
    and Natural Resources,
  • Donate unwanted plants and animals to a school, nature center, aquarium or zoo, or return them to the retailer if possible.
  • Swap unwanted plants and animals with another aquarium owner or water garden hobbyist.
  • Caution the new owner of donated or swapped plants and animals against releasing them into the natural environment and suggest alternatives for disposal.
  • Avoid composting aquatic plant material due to the risk of spreading seeds or plant fragments to natural areas.
  • Contact a veterinarian or pet retailer for guidance on humane disposal if you can't rehome an animal.
  • Learn to identify common invasive plants and animals in the exotic pet, aquarium and water garden trade, such as Brazilian elodea, hydrilla, fanwort, red-eared sliders, goldfish, koi and lionfish, and seek native alternatives.
  • Take photos and report infestations to the iMapInvasives database: (leaves DEC website)
  • If you own or operate a pet store consider sharing the Pet and Aquarium Owner tip strip (PDF) with your customers.

Moss Ball Recall

The New York State Department of Environmental Conservation (DEC) is urging pet and aquarium stores as well as consumers to immediately remove and properly dispose of commercially purchased "moss balls" for aquariums; after invasive zebra mussels were discovered inside and on some of these products, as reported by the U.S. Fish and Wildlife Service. Consumers should be advised that moss ball products purchased from PetSmart and Petco may be subject to a voluntary product recall. It is important that you remove any "moss balls" -that were purchased within the last year- from your tank and properly dispose of them. Zebra mussel larvae are so small that you cannot see them and they can quickly take over your tank, damage filter systems, and if released cause great harm to waterbodies. Here's what you should do:

  • Dispose of any moss balls from your tank in a sealed garbage bag. Other aquarium plants should be disposed of too as they may harbor zebra mussels from the moss balls.
  • If you're able to disinfect your tank (after safely removing any animals) you should apply household bleach -one cup of bleach per gallon of water- and let it sit for 10 minutes before disposing of water down the sink or toilet.
  • Be sure to disinfect filters, gravel, and structures with a solution of bleach as well. Water from filters must also be treated with household bleach before disposing of water down the sink or drain.
  • For larger tanks that cannot be easily drained, please email for instructions.
  • If you find zebra mussels in your tank or on a "moss" ball, please take a photo if possible and report the observation, via email at, or by phone at (518) 402-9405.
  • Remember, just because you can't see zebra mussels does not mean their larvae are not present.

Additional Resources