From Pet to Pest!

Did you know that fish are one of the most popular pets in America? And of species of fish, Goldfish are the most popular (American Veterinary Medical Foundation). There is only one problem with having goldfish as pets; dumping them! Properly disposing of Goldfish, whether alive or dead, can cause issues for ponds, streams and lakes in Ohio. Goldfish are a non-native and invasive species of fish, meaning they are not from this area originally and pose many problems to other native species in Ohio (Beatty 2017). An established Goldfish population has already been established in Western Lake Erie and could inhabit bodies of water near you if they are not properly disposed of (Trautman 1981).

Dumping or flushing of live Goldfish into toilets or into bodies of water can directly introduce them to our streams and lakes. By doing so, a non-native species is added into the food web among native species. These invasive Goldfish can grow to massive sizes by taking food resources from native species of fish (Moyle 1976). They have also been found to eat the eggs of other native fish species even further so hurting their future populations (Moyle 1976). Goldfish also occupy habitats that native fish use for reproduction as well as shelter and are even able to reproduce with the Common Carp to produce larger, hybrid species that are equally as detrimental to native populations (Moyle 1976).

Photo 1: Massive Goldfish (Larimer 2015).


Dumping or flushing of live Goldfish can also be detrimental to bodies of water as these non-native species can introduce parasites and other diseases that our Ohio fish are not accustomed to (Washington Department of Fish and Wildlife). These fish, originally from Asia, as long as the water they live in inside tanks, carry potentially harmful diseases that we do not want shared with our native species of fish and if introduced, could spread these diseases!

As Lake Erie has already been affected by Goldfish, there is an even greater threat to highly sought-after game species of fish (Washington Department of Fish and Wildlife). Alongside this, there is also a threat to smaller bodies of water in Ohio that are currently unexposed to Goldfish. There have been cases in Colorado and other states where a few Goldfish in a small lake escalated to over 3,000 in just a few years (Block 2015). With Ohio having so many streams and other bodies of water, it is important that we keep Goldfish out of them, whether dead or alive to ensure the safety of our native species of fish.

In an NPR article, fish biologist Ben Swigle, recommends to humanly dispose of these fish. The method he suggests is to freeze the deceased fish overnight and dispose of it in the trash (Block 2015). There are also options to see if pet stores will take the fish back or pass on the fish to a new home.

No matter which option you choose, it is important that these highly desired pets are properly disposed of and do not end up in Ohio’s bodies of water as they have the potential to have long term effects on our native ecosystems and species. So, next time you or a friend goes to toss a Goldfish in a lake, think twice!



American Veterinary Medical Foundation. 2012 U.S Pet Ownership & Demographics Sourcebook.

Beatty, S. J., Allen, M. G., Whitty, J. M., Lymbery, A. J., Keleher, J. J., Tweedley, J. R., Morgan, D. L. (2017). First evidence of spawning migration by goldfish ( Carassius auratus ); implications for control of a globally invasive species. Ecology of Freshwater Fish, 26(3), 444-455. doi:10.1111/EFF.12288

Block, S. (Host) 2015, April 8. From Pet to Pest, Goldfish Tip Scales of Survival in Lake’s Ecoystem [Radio Broadcast episode].
Washington Department of Fish and Wildlife; Aquatic Invasive Species. Carassius auratus (Wild Goldfish).

Larimer, S. 2015, June 25. Discarded pet goldfish are multiplying. The Washington Post.

Moyle, P.B. 1976. Inland fishes of California. University of California Press, Berkeley, CA.

Trautman, M.B. 1981. The Fishes of Ohio. Ohio State University Press, Columbus, OH.

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