No Dumping

By Francis Skalicky | April 21, 2015
From Missouri Conservationist: May 2015

Missouri waterways are troubled by illegal aquarium dumping Imagine casting your fishing line into one of Missouri’s streams or reservoirs and coming up with something … unexpected. In 2007, anglers hooked piranhas at two different locations at the Lake of the Ozarks. A woman fishing at Troost Lake, Kansas City, in 2011, reeled in a large, brightly colored goldfish. And in 2013, anglers caught one alligator and saw two others while fishing at Pomme de Terre Lake in Hickory County.

Though separated by dates and geography, these events have one thing in common: aquarium dumping. Pouring the contents of aquariums into close-to-home waterways may seem like an inconsequential and humane option for those overwhelmed by caring for aquarium-bound pets, but it can threaten aquatic habitats and make life difficult for native aquatic species.

“Missouri’s native fish and wildlife have developed through a long history of diversity and natural selection,” said Andrew Branson, a fisheries program specialist for the Missouri Department of Conservation. “Invasive species can quickly disrupt the entire ecosystem by creating changes that native wildlife are not designed to combat.”

There Goes the Neighborhood

In Missouri, the preferred habitat of piranhas, goldfish, alligators, and other nonnative exotic pet fish, reptiles, and amphibians is aquariums. Some species are bred to be hardy and highly adaptive to ensure longevity inside an aquarium. These survival traits, which are beneficial in captivity, can create problems if the animals are released from a residence into local waters.

 “Some aquarium species are among the hardiest fish and plants in the world,” said Kenda Flores, an aquatic habitat specialist for the Department of Conservation. “Aquarium owners and importers who dump them are introducing tough, nonnative species into our state waters.

“These species compete with native fish populations and local aquatic plant communities and threaten their diversity and abundance. They can change whole ecosystem processes by upsetting the natural balance. This lowers the ecosystem’s ability to cope with different pressures and impacts. All of this can result in lower biodiversity and an unhealthy ecosystem.”

What’s in Your Water

Judging from what’s been netted in biologists’ surveys and anglers’ fishing trips, the species entering the state’s waters from aquarium dumping are diverse.

“I’ve managed the St. Louis Urban Fishing Program for 28 years, and I can recall a variety of nonnative species that were likely introduced from aquariums,” said Kevin Meneau, a Department of Conservation fisheries management biologist. “These include pacu (a relative of the piranha), piranha, plecostomus (a South American catfish), koi, Chinese mystery snails, a red-tailed shark, and caiman.”

Dumping: Not Just for Fish

When the contents of an aquarium are transferred to the nearest pond or stream, exotic aquatic animals aren’t the only problem. Hydrilla (Hydrilla verticillata), a once-popular aquarium plant now hated for its aggressive growth, has been found in several ponds in Greene County and elsewhere around Missouri. In other states where hydrilla has become established, this herbaceous perennial has severely impacted sport fishing and other water-based recreation. Because the plant’s reproductive parts can be transported by wildlife, it’s unclear how it arrived in Missouri. However, there’s no doubt that the hydrilla plants discovered in Missouri — like those in other states where it’s more prevalent — have a lineage that can be traced to plants that once adorned aquariums. Elodea, giant elodea, and Eurasian watermilfoil are other aquarium plants that often end up as freshwater problems.

Spreading Disease

Aquariums can be a cocktail of parasites and exotic diseases that can pose serious problems for native species. For example, African clawed frogs are popular aquarium pets that can carry the Chytrid fungus. This can be fatal to hellbenders, a Missouri amphibian that’s already in trouble. Chinese mystery snails, goldfish, arrowanas, and pengasius catfish are among a long list of other exotic aquarium species that potentially harbor diseases and parasites that can be harmful to other fish and, in some cases, humans.

A Nationwide Issue

Aquarium dumping isn’t limited to Missouri. Pam Fuller, a research biologist for the U.S. Geological Survey, says studies show that 30 percent of all the nonnative fish in the nation’s waterways get there from aquarium dumps. The state of Florida has given up trying to eradicate hydrilla and has spent millions on merely trying to keep this fast-spreading plant under control.

Misplaced good intentions are at the heart of this problem. Public attitude surveys have repeatedly shown that Missourians care about conserving forests, fish, and wildlife, which indicates that no one is dumping an aquarium into a lake or stream with the intention of ruining bass and crappie fishing in the area. Nor are they hoping the exotic plants leaving their fish bowl will grow to the extent that they interfere with the operation of recreational boat motors and clog municipal water intake devices for nearby communities. They simply view their action as a kindhearted solution to unforeseen fish-care problems.

“People want to get rid of fish because they outgrow their tank, they want to go back to smaller fish, or a fish becomes troublesome for its tank mates and they want to get rid of it so it doesn’t hurt or kill other fish,” said Karl W. Keller, II, vice president of Petsway, Inc. in Springfield. “Before purchasing a fish, buyers need to consider how big the fish will eventually become, the cost of properly housing and maintaining the fish, and also the temperament and compatibility of new fish with their potential tank mates.”

Do Your Homework

“You should always research what you plan to purchase prior to buying,” said David Whitcraft, the president of the Heart of America Aquarium Society, an aquarium club based in Kansas City. “What type of water does it prefer? Where in the world did it come from? What does it eat? How large does it get? How aggressive is it? These are all questions that need answers.” Whitcraft said some people have false perceptions about the growth potential of captive pets and this can lead to post-purchase problems.

“The main thing people need to look at is the maximum adult size of the aquatic creature in question,” he said. “There is a myth in this hobby that the size of the tank will limit growth or that the animal won’t outgrow the tank. This is like saying if you put a puppy in a pen and never let it leave, it will never grow to be a full-sized dog. Of course it will grow, but it won’t be happy.”

Another misconception is that exotic fish accustomed to tropical climates — or, in the case of aquariums, artificially produced tropical climates — won’t survive Missouri’s winters if dumped. Flores said that’s not always the case. Sometimes they find “refugia,” a biological term for pockets of habitat that provide ideal living conditions for certain species.

“For exotic fish, it might be a spring that keeps them warm in winter and cool in summer,” she said. “Sometimes they are dumped in a body of water that they can easily adapt to and survive from one season to the next.”

And sometimes the species show adaptive abilities they weren’t known to have.

“The northern snakehead fish (Channa argus) is a good example of that,” Branson said. “These fish have been found to reproduce in waters of the northern United States that were thought to have been too cold for it.”

Alternatives to Dumping

Though the nearest pond or lake is not a viable alternative for a domestic fish situation that’s gone awry, there are alternatives.

Keller said, in most cases, his store will take back a problem fish. But even if a fish can’t be returned to a store, there are other options.

“The first place to look is the local aquarium club,” Whitcraft said, adding there are several quality clubs in the Midwest. “People are looking to buy, sell, trade, and give away fish and aquarium products all the time. They have regular events, monthly meetings, auctions, and swap meets. Outside of that, there are many people looking to purchase or give fish away on Craigslist.”

Against the Law, Against Nature

There are state wildlife regulations prohibiting the release of nonnative species into the wild, but the reasons not to dump an aquarium go far beyond violating laws in a codebook.

“Most people probably think they’re doing their fish a favor by releasing it,” Branson said. “However, people don’t realize their fish could create problems for native fish.”

Sometimes, these problems have long-term consequences.

“The damage done by invasive species can take many years for native wildlife and the environment to recover from, if they can recover at all,” he said.

Learn more about problem plants and animals at

This Issue's Staff

Editor In Chief - Nichole LeClair Terrill
Editor - Angie Daly Morfeld
Art Director - Cliff White
Staff Writer/Editor - Bonnie Chasteen
Staff Writer - Heather Feeler
Photographer - Noppadol Paothong
Photographer - David Stonner
Designer - Stephanie Thurber
Circulation - Laura Scheuler