Are GloFish bad for the environment?

Back when I lived in California, I bought a 28-gallon fish tank. I always liked keeping fish, but since I have been in Madison, Wisconsin I haven’t found the opportunity to fill the tank up and stock it with the little swimming stress-relievers. Finally, the place for the tank is ready in my basement room, so on Sunday I took a trip to the local aquarium to look for just the right fish for a geneticist to place beneath a subtle neon-on-black painting he bought in Thailand. The answer to that is nothing other than GloFish®, a genetically engineered zebra fish that expresses fluorescent proteins. The tank isn’t quite ready yet, but I have been ready for years.

It used to be that to get brightly-colored fish in your aquarium you had to go with saltwater – which has a much bigger cost and effort – not the kind of thing for novices. Taking zoology at UC Davis as a freshman convinced me that I wanted to have a saltwater aquarium with creatures from every phylum, however volunteering to take care of the aquariums in Storer Hall convinced me otherwise. Accidentally scare your cuttlefish and you have a tank full of ink to clean up! I decided to stick with freshwater.

With the advent of the first Glofish® in 2003, however, the aquarium scene changed. Now freshwater aquariums can have brightly-colored fish, too. Plus, zebra fish are easy to take care of, and it also gives me something cool to finally use that black light for. There is no shortage of accessories, special tanks, and lights you can buy for these fish, leading me to wonder whether the fish are the real money-maker or the toys you get so you can set up a tripped-out tank?

GloFish® are among the first genetically engineered animals to be commercialized. Not the first, however, as according to Wikipedia there was another fluorescent fish made by a different company that sold like hotcakes in Taiwan back in 2003. Over 100,000 bright green medaka fish sold in less than a month, proving that there was quite a market for these novel ornamentals. As the GloFish® began selling and upgrading their colors here in the U.S., naturally, the Center for Food Safety sued to stop it. In 2005, their lawsuit was dismissed. California banned the fish with a law intended to stop genetically engineered salmon, later relented, and then turned around and informed the company that they would have to complete an expensive environmental review on top of previous evaluations. The company decided it wasn’t worth the cost, so they are available everywhere else in the U.S. except California.

Meanwhile, academics started thinking about how to use these brightly-colored Danios to teach about concepts in genetics, from Mendelian inheritance to statistics and genetic engineering itself. In fact, Glofish® have several good things going for them. First, the development of the fish was based in environmentalism, and were originally developed to detect toxins in water. Detecting common contaminants would be as easy as putting a fish into a sample of water and waiting to see if it glowed. Later, they realized that they looked really cool. I once thought the same thing when I first saw the glowing green muscles of fruit fly larva crawling under a dissecting microscope in genetics lab, only to realize that most people don’t keep Drosophila as pets.

Second, they are currently the only form of animal* genetic engineering that the average person can see in their lives and become familiar with. Sure, there’s food, cotton, and medicines – but none of these are things that allow you to really see the difference and pique your curiosity about the technology. That curiosity can lead to, of all things, learning about and becoming comfortable with something that is becoming an increasing part of all our lives. And a Google Trends analysis proves it – far more people search for information on Glofish® than they do the “Enviropig” or the Aquadvantage Salmon – two other prominent examples of genetically engineered animals.

Genetic engineering? Oh yeah I’ve got some of that in the fishbowl in my kid’s room.

Over the past nine years, there have been no reports of any environmental incidents involving GloFish®, and it seems for the most part the usual anti-biotech groups have left it alone after their defeat in court. Recently, however, a new glowing fish from the same company have reignited environmental concerns about these ornamental fish. There is now an “electric green” (GFP) Tetra fish available in stores, and this has some people worried. Unlike the zebra fish which prefer tropical waters, Tetra fish are more comfortable in the cooler temperate waters in North and South America. The Washington Post aired these concerns, saying it “may or may not have an unfair advantage in the wild.” Is it that uncertain?

One of the problems with journalism on scientific topics is the tendency to put together “he said, she said” articles, that quote people on either side of an issue and frame it if it was a political debate. On one side, you have arguments and evidence being put forward, and the other side just has to say “nuh-uh.” We see these kinds of stories come up when debating evolution, global warming, etc. It is much harder for the reporter to do the research and evaluate where the evidence points to. So are GloFish® likely to pose a significant risk to the environment over their non-genetically engineered counterparts? Let’s stack up the evidence.

The fish have reduced fertility, both because they have been sterilized through pressure treatment while eggs, and when they do reproduce they have fewer offspring. The fish also use energy less efficiently due to the energetic cost of producing fluorescent proteins. Finally, they are twice as likely to succumb to predation, as determined by research conducted during the regulatory process by Jeffrey Hill, a fishery and aquatic scientist at the University of Florida. No arguments were presented from the other side that the genetically engineered tetra fish would actually have an advantage over other fish in the wild. True, they can be released, and some could survive and reproduce, but it appears that they would be unlikely to have a significant impact on other fish of the same or similar species any more than non-modified tetra fish. That, I think, is the key issue – whether they differ in terms of harm to genetic diversity and other measures of environmental impact. (Technically, an extra gene in the gene pool is an increase in genetic diversity.) But this by itself does not unequivocally establish that no harm could be done.

Alternately, the focus on genetically engineered fish can be seen as a distraction from the ever-present problems with invasive species that we currently grapple with around the world. While environmental groups sue to stop genetically engineered crops, fish, and more, pets and weeds and all manner of invasive species causing harm are being overlooked because they are more “natural.” With the limited amount of time and resources, could there actually be more harm done to the environment by trying to put out the light of glowing fish?

*There are a few plants that people can become familiar with, such as purple carnations and blue roses. But they don’t last as long in your house as pet fish!

Follow Karl Haro von Mogel:
Karl earned his Ph.D. in Plant Breeding and Plant Genetics at UW-Madison, with a minor in Life Science Communication. His dissertation was on both the genetics of sweet corn and plant genetics outreach. He recently moved back to his home state of California. His favorite produce might just be squash.