Are your classroom crayfish, fish or plants invasive?

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Are your classroom crayfish, fish or plants invasive?

As we get into the swing of the school year, teachers around the state are ordering supplies for science labs and selecting pets and plants for classrooms. Michigan’s Invasive Species Program reminds you to use caution in selecting live specimens and to avoid releasing specimens, pets or aquarium plants into the wild.

Keep invasive species out of the classroom

Did you know?

Close up of an aquarium showing a goldfish in the center, a silver fish above, in front of aquatic plants.

Some common classroom organisms are considered invasive in Michigan because they are not native and can cause harm to the environment, economy or human health.

In Michigan, 56 invasive species are listed as prohibited or restricted, which means it is unlawful to possess, introduce, sell or offer these species for sale as live organisms except under certain circumstances.

Invasive rusty crayfish and Eurasian watermilfoil, an invasive aquatic plant, were once common elements of biological supply kits and aquarium habitats. Now, unfortunately, they also are common in waters throughout the state, altering habitat, disrupting ecosystems and recreation, and costing millions to control. It’s likely that aquarium owners releasing these organisms into local ponds or streams contributed to these infestations in Michigan.

Despite the laws, these and other invaders not yet confirmed to be in Michigan, including hydrilla, Brazilian elodea and giant African snails, are marketed online to teachers and aquarium enthusiasts.

Why be concerned about invasive species in the classroom?

Many teachers order curriculum kits, including plants and animals, from biological supply companies. These kits can have generic content labels, like “crayfish and aquatic plants,” rather than species-specific names. In such cases, teachers wouldn’t know if the species were prohibited or restricted in Michigan.

Not all classroom or retail suppliers maintain updated lists of state-regulated species or identify their specimens correctly, so it is possible for teachers to unknowingly order and receive plants, animals or fish that are not legal in Michigan.

The Department of Natural Resources has taken steps to stop the importation of invasive species through online trade, including partnering with the Great Lakes Commission’s GLDIATR web crawler project.

However, what is available online changes daily, and pets and plants can also be purchased through chat rooms, marketplace sites and exchanges. Ultimately, it is consumers’ responsibility to be familiar with state law to ensure they are not receiving prohibited or restricted species.

What you can do

  • Before ordering live organisms, be sure to know which species are prohibited or restricted in Michigan.
  • Choose organisms that are clearly identified by scientific names, not just common names, which can vary by supplier.
  • Check stock when it arrives.
    • Ensure each specimen is properly labeled.
    • Rinse plants in the sink.
    • Remove and dispose of packing materials and any attached organisms or plant fragments in a sealed bag in the trash.
  • If you suspect you may have received a prohibited or restricted plant species in a shipment, contact the Michigan Department of Agriculture and Rural Development immediately at 1-800-292-3939 or
  • If you suspect you may have received a prohibited or restricted fish, mollusk or crustacean in a shipment, contact Lucas Nathan at the DNR, 517-599-9323.

Adopt proper disposal practices for all pets and plants

What happens to classroom pets after school lets out?

In a survey conducted by Oregon State University Sea Grant, 40 percent of teachers disagreed with the practice of euthanizing classroom pets when no longer needed in the classroom. If pets and plants had not died on their own, the most common means of disposal included giving them to students or other teachers, putting them in the trash or releasing them to the wild.

In a 2016 Michigan State University survey of 157 science teachers, 18 respondents reported using live crayfish. Respondents indicated using risky disposal methods similar to those in the Oregon study on five occasions.

These disposal options are especially problematic if the pet or plant is an invasive species. Giving classroom pets and plants away to others places the problem in someone else’s hands and could lead to an eventual release. The only appropriate method to dispose of dead plant or animal specimens or live plant material is in a sealed bag in the trash, never by composting.

What’s wrong with returning them to nature?

Even noninvasive pets and plants should not be released in the wild. Though release seems to be a humane option, most nonnative pets will not survive in Michigan’s environment due to climate, predators or the inability to find appropriate food and shelter. Pets or plants that easily adapt have the potential to become invasive – think of Burmese pythons in the Florida Everglades or the invasive kudzu vine throughout the southern states.

Even if a pet or plant itself is not invasive, it can introduce diseases that affect native wildlife.

In 2007, concern about the spread of fish disease prompted Michigan to limit the release of both native and nonnative live fish into Michigan waters. To prevent the spread of viral hemorrhagic septicemia, or VHS, it is now illegal to place a live fish in Michigan public waters without a permit, except in certain circumstances such as releasing a freshly caught fish into the body of water where it was caught.

Best practices for pet and plant disposal

RIPPLE program aquarium

Michigan’s Reduce Invasive Pet and Plant Escapes (RIPPLE) project, cosponsored by MDARD and Michigan State University Extension, aims at educating both consumers and retailers about proper containment and disposal methods for plants and animals associated with the pond and pet store industries. RIPPLE advises to:

  • Properly dispose of all plant materials removed from ponds, water gardens or aquariums. Seal plant materials in a plastic bag and place them in the trash, not the compost pile.
  • Give or trade unwanted pets and plants to an environmental learning center, aquarium or zoo, or a knowledgeable hobbyist.
  • Contact a veterinarian or pet retailer for guidance on humane disposal of animals.

Visit MSU’s RIPPLE website for educational materials and information on pet and plant disposal. More information on Michigan’s prohibited and restricted species is available at

Spotlight: Red swamp crayfish

Red swamp crayfish

Since 2017, Michigan has been in a costly battle to prevent the spread of invasive red swamp crayfish, likely introduced as released bait or live food or from classroom release.

Though native to southern states, they are considered invasive in Michigan because they compete aggressively with native crayfish species for food and habitat, and their deep burrows can damage infrastructure such as dams, levees, irrigation systems and personal property.

Download this red swamp crayfish poster for helpful identification and disposal information. Learn more about invasive crayfish in the aquarium trade with this RIPPLE brochure.