Ames Free Library

"Where the Community Connects"

Digging Deeper: Something Fishy

 Last weekend I cleaned my goldfish pool which really needed to be refreshed. Although I felt very guilty for its neglect, the task required a chunk of time, something that has eluded me lately. The container, a converted planter, holds about 20 gallons of water, a potted pickerel weed, and three fish. A solar-powered fountain keeps the mosquito larvae in check, and a snail sometimes visits. Here it is on my patio in midsummer.


While I am sure many of you enjoy relationships with pet animals, you may be wondering how this anecdote relates to “nature” and the library. Let’s start with the library connection. Before they moved to Pembroke, my fish had been library fish, that is, they were the fish who had been living in the Ames Free Library’s reflecting pool. Here is one member of the school on March 18 right after the pond ice broke for the season.


You may have watched these fish when you visited Queset Garden . . . at least until the increasingly murky water obscured its denizens. The shallow pool’s location in full sun, its lack of circulation during the drought, and its likely exposure to fertilizer runoff all increased the probability of an algal bloom . . . and what a bloom it was! By June 1, the pool’s water radiated green.


Arrangements were made to drain and powerwash the pool, but before doing so, twenty-one fish were captured and offered for adoption. On July 23, they waited in stark quarters while word went out via Facebook to potential families. 


In no time, six families offered shelter and care. This divided the school, but all the fish had a buddy and a second chance. Some didn’t survive the transition, but the majority adjusted to a new life in fish tanks and artificial ponds.



Courtesy:  Megan Tully

Long before this mass adoption, a library patron wondered, “How did the fish get to the library’s reflecting pool?” It’s a good question for which I have no definite answer. One frequently-proposed theory for fish dispersal is that waterbirds inadvertently transport fish eggs that cling to their feet and feathers to new bodies of water. While this may very well be true, a recent review of scientific literature found no solid research to verify the hypothesis. Here’s your chance to devise an experiment.

At least two recent studies point to a different route: fish eggs can reach new locations when they are eaten by birds who later poop them out! It may seem unlikely that an embryo could survive the journey through a water bird’s digestive tract but, apparently, some do. In 2019, a team of Brazilian scientists tested this theory by mixing the eggs of killifish, a very resilient freshwater species, with food given to coscoroba swans. According to this summary in Smithsonian, 650 eggs went in, 5 came out, and 1 egg hatched into a normal fish. The percentage of live dispersal might be low, but it’s not insignificant when multiplied by the vast number of fish eggs and potential bird dispersers.

In July 2020, a set of Hungarian researchers fed carp eggs to mallard ducks. Their experiment, which is described in Scientific American, yielded three “normal baby fish.” Keep in mind that the common goldfish’s ancestors were carp.

Another possibility, I suppose, is that the Queset Garden fish were delivered with the pool water that is periodically trucked in. I know nothing about the source of this particular water, but some companies do extract from ponds. Just think how many aquatic creatures have traveled in ships’ ballast!

All the same, I suspect the origin story of these goldfish involved pet abandonment.  I believe most pet adoptions begin with good intentions – a desire for companionship, an appreciation of natural beauty, an act of kindness — but human lives change frequently, and animal care can be more challenging than we anticipate. Large parrots, for example, can live 50 years or longer. Can you predict where and how you’ll be living in 50 years? When the human can no longer care for the pet, or care for it in a way that it thrives, some psychological gymnastics begin: Wouldn’t the animal be healthier or happier if it were “free”? I know. I’ve had these feelings (and acted upon them) when I was younger. In fact, many released pets languish and die, albeit out of our sight. When they do survive, they can create new problems.

My young fish seem so benign in their mini-pool, but these same fish can grow to be huge when released in the wild. Take a look at this image from the US Fish and Wildlife Service.


A 14-inch goldfish removed from the Niagara River.

Courtesy:  USFWS

Goldfish introduced into lakes, ponds, and rivers outcompete native fish by having enormous appetites and few predators. They also reduce water quality and plant life by stirring up mud from the bottom. This New York Times article offers a mix of goldfish history, fish behavior, current research, and management practices for this invasive species. The scale of the problem is startling: during November, 2020 one Minnesota county removed “as many as 50,000 goldfish from local waters.” [See The Guardian, 7/21] “It is estimated that as many as 200 million goldfish are bred each year . . . .” If only a small percentage are “rewilded,” they’ll pose a big challenge to our waterways and wildlife managers.

Imported Asian plant and animal species seem to get much of the invasive spotlight, but ecological havoc moves in all directions. Consider the bluegill’s journey as told in “The Prince, the Mayor, and the US Fish that Ate Japan.” A well-intentioned gift of bluegills from Chicago’s mayor Richard Daley to Japanese Crown Prince Akihito has become a huge ecological problem in Japan’s waterways. The fifteen fish who arrived in Japan in 1960 were bred and released into the wild “as a new game fish nicknamed ‘the prince fish.’” This small population multiplied . . . and multiplied.  “By 2007, the prince fish population reached an estimated 25 million.” Native Japanese fish didn’t fare as well.

My fish won’t be setting a fin in any Massachusetts waterways. They will move inside for the winter and, hopefully, receive a larger pool next spring, one that will give them room to swim and to grow. Arranging for their support leaves me with mixed feelings, though. I regret the wastefulness – the purchase of equipment to sustain pets while native fish languish. Tanks, filters, pumps, and other paraphernalia can hardly be considered ecologically sound.  On the other hand, I cannot look at these goldfish as objects, especially since we’ve become acquainted with each other. When they swim to the surface to greet me (and get some dinner), I see individuals who desire life just as I do. 





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