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Jason Smith: 603-271-2501
June 7, 2013

Exotic Wildlife and Plants - OK to Enjoy, but Be Responsible!

By Jason M. Smith, Chief, Inland Fisheries Division, N.H. Fish and Game Department

Exotics brochure

The popularity of having exotic plants and animals as pets is a trend that can potentially put our native fish and wildlife habitats at risk. It is important for the public to be aware that invasive fish and wildlife can disrupt the local ecology and can out-compete native species. They should never be released.
Almost everyone has found enjoyment in stopping to view a water garden or an aquarium at a local restaurant or spa. There are local contractors that will come to your home and install a peaceful, cascading waterfall that includes a pond liner, pump and filter assembly. Many home improvement stores have ready-made kits for you to install on your own.  These water gardens add a very relaxing and aesthetically pleasing landscaping touch to a home or business. We have a lovely "Planting for Wildlife" habitat/pond area at the entrance to the Fish and Game Department in Concord.  It's important to note that our water garden does not include any invasive fish (in fact there are no fish at all in it) or invasive plants.
When you add fish to water gardens, it's another story that can go like this: It’s summer; the temperatures are hot and all seems wonderful. But in a few months, the temperature will be falling.  What will people who have added fish to their water gardens do with these fish when the season changes?  I hope they are planning ahead and have an environmentally safe plan for holding those exotic fish and plants through the winter?  In many cases, not having a plan or the logistics to store these fish appropriately leads to a problem.  Understandably, people become emotionally attached to these "pets."  If they cannot find alternatives to maintain them, euthanization is unthinkable.  Many times, these fish are released into local fire ponds at housing developments or city parks.  Or worse, into local ponds and streams!  This irresponsible action can have devastating results, because some of these exotic fish or ornamental plants and animals that people enjoy looking at in their aquariums or water gardens have become aquatic nuisance species problems, disrupting the native plant and animal communities. Invasive wildlife can disrupt the local ecology and can out-compete native species due to higher tolerance to poor water quality and/or high reproductive rates.
Another scenario: Most families I know have at some point enjoyed an aquarium for pet fish.  It is easy to understand the popularity of this practice, because of the peace, tranquility and relaxation that they provide. Many parents use aquarium fish to teach their children the responsibility of pet ownership prior to purchasing a dog or cat. But what happens to these exotic fish when once-responsible owners, with good intentions, no longer have the interest in caring for them?  When circumstances change and someone is forced to move to a new location where having these pets is not an option, where do these fish end up?

Just recently, I received a call about a fish kill at White’s Park Pond in Concord.  Having grown up in Concord myself, I knew exactly what pond the park manager was referring to.  In fact, I remember visiting this very pond on my bicycle to enjoy these fish myself.  When exactly? I won’t tell, to prevent from revealing my age! When I arrived at scene of the recent incident, I observed what I anticipated.  A shallow pond with an unusually high number of (overpopulated with) goldfish, koi and bluegill, crowding the perimeter of the pond guarding spawning nests.  Having enjoyed the White’s Park Pond fish experience in the past, I was saddened to see what was happening.

My professional career has blessed me enough to allow me to work with fish every day.  I chose this career because I believe in conservation of New Hampshire fish and wildlife resources. Years ago, I never would have put much thought into how these fish may have gotten there, and certainly wasn’t aware of the risk these fish were presenting. But the fact is, many of these exotic species are present due to the acts of people with big hearts, good intentions or people who are simply unaware of the damage it can cause. As a long time dog and aquarium owner myself, I would never condemn anyone for loving their pets. Unfortunately, there is no shelter for fish to reside until adoption, if the original owner can no longer care for them.

Koi and goldfish are exotic species that must not get into state waters.  One reason is that koi and goldfish can present a health risk to native fish species. Ornamental fish raised in captivity have developed resistance to certain diseases, due to the typically stress free environment of an artificial setting. Koi and goldfish that appear healthy can be carriers of pathogens such as Koi Herpes Virus (KHV) and Spring Viremia of Carp Virus (SVCv). SVCv, in particular, can cause serious problems in wild baitfish populations. Many of our wild and native fishes have never been exposed to some of these emerging pathogens. Therefore, many of our wild fishes have never had the opportunity to develop an immune resistance to these potential diseases. This is why all baitfish and fish being imported for aquaculture must pass a pathological inspection prior to an import being approved.

The New Hampshire Fish and Game Department, by Administrative Rules, lists all ornamental or aquarium fish as “non-controlled” provided they remain in a “closed system.” These same rules prohibit the release of any fish and wildlife without a permit so to do.  Some other states, Maine, for example, prohibit the possession of koi completely. Please help us protect the natural resources of New Hampshire by being conscious of the fact that those plants and animals you enjoy in your water garden or aquarium are illegal to release into the wild, where they threaten native wildlife.
For more information on disposing of unwanted aquarium and pond plants and animals, visit to download the brochure "Don't Leave Them Stranded."

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