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!


  1. In a related topic which you might be able to address with your background in plant genetics, what about Christmas trees? When I first read about the early results of inserting bio-fluorescent genes into animals, the first thing that popped into my head was what a great, cool way to light a Christmas tree! It’d reduce both power consumption (I presume) and reduce fire hazards. And no need to wind and rewind long strings of light. I thought that surely somebody would work on this potential commercial bonanza and I’d read about it in a short time. But it’s been years and nada, zip, NOTHING! Perhaps I missed reports, perhaps there’s a technical reason I’m not aware ofmakind it impossible or prohibitively expensive, perhaps no one else had this brilliant 🙂 idea. Can you answer this quandry? Oh, and could luminescence of different colors be expressed in the same tree?

  2. I have heard news about the potential for having bio-luminescent genes inserted into trees that would be planted in cities to reduce the need for street lighting, but as far as I know no one has achieved this. The GloFish doesn’t really glow on its own, but requires an input of UV or blue LED light that the proteins absorb and re-emit. So to have the trees glow on their own would require a little extra work. It would be possible to insert such genes in Christmas trees, and supposing you can get the tree to glow on its own, it would be pretty fantastic looking. Yes, you could have more than one color in the same tree, and by using tissue-specific promoters you could make the colors show up in different places in the tree, like green in the base of the needles, and red on the tips. So these things certainly seem possible, but it would be complicated, and require a lot of research!

  3. Thanks for your reply. After I posted I got to thinking about possible complications and I wondered what the set up for the UV would entail: how many lights arranged how, power consumption, safety issues both about whether it would be kid-proofed and possible skin cancer risks. Imagine having to apply UV protection lotion to enjoy your tree! I suppose some of that would be less of an issue with blue LED lighting. Well, pass the idea along to anyone who might be able to make it work. But when I hear in a few years that someone is selling GloTannenBaum trees I’ll know it was all my idea :)! Yes, fantastic is a good word, so’s marvelous.

  4. There may not have been any environmental problems, but how many heads have been bitten clean off? How could you write post on GloFish without mentioning the dangers of decapitation?
    I’d like to have some GloFish, but because I have a cat that can open some doors and tends to find & eat things he likes (he has defoliated my lychee seedlings, mowed down a clump of an aloe, and ate a very old spider plant), I’ve never gotten any. Wouldn’t want this to happen!

  5. And something I forgot to add: about them being the only genetic engineering that people can really interact with, the Applause rose counts too yes? It seems you can get them here if you’re in the market for a big bouquet.

  6. Yes, of course you are right! In preparation for talking to some animal biotech folks this week, I was thinking in terms of animals. I’ll correct that in the post! There are also the purple carnations, too. 🙂

  7. The Greenpeace cartoon, while inaccurate and ignorant, doesn’t make me any less likely to get glowing fish. I’d love my cat to get all badass with superpowers like that. In actuality, she will probably be less enthused than I about our new pets.

  8. This is totally OT, but this is the only access I have to a genetics expert and so I’ll exploit it. I am currently rereading “Time Enough for Love” (1973), a SF novel by Robert Heinlein. In it are three storylines that deal with genetics. Two of them deal with things that are probably too technologically difficult to achieve any time soon, perhaps ever. However, one is simple enough that it may be doable, at least with animal models if not with humans–legal and ethical issues. In the book, geneticists take a cell for cloning from a male, remove the Y-chromosome, replace it with the X from another cell of his, and the result is an opposite sexed identical twin. Now, from my reading I understand that X-chromosomes may not be interchangeable in a female genome, that they behave differently at times. As this was written about 40 years ago, RH’s knowledge is primitive in comparison to that of 2012, and my understanding is inadequate to have a valid opinion. What’s yours?
    BTW, reading old SF is fun for what in some areas is wild optimism about will be achieved in a certain period of time and in others the pace of change is absurdly slow. I once read a short story by Arthur C. Clarke, from early in his career, that had a spaceship from well in the future which was controlled by a computer that used vacuum tubes! Other contemporary authors knew better, so he should have,too! Well, I hope that this isn’t

  9. Hi Gerald, thanks for commenting. Just a quick note – if you ever want to start an off topic conversation, you can post in the Forum.
    I love science fiction. It can certainly be a way for us to consider both the optomistic and pessimistic possibilities of new technologies. Who would have guessed that we’d have glowing fish!? If you’d like to read more genetic themed sci fi, check out Copernick’s Rebellion by Leo Frankowski. It’s one of my all time favorites.
    As for the chromosomes in the story – I think it would work (with all other needed technologies in place, etc). In females (or males with more than one X), one of the X chromosomes goes into an inactive state, called a Barr body. In males, their X stays active so there shouldn’t be a problem there.

  10. Randomly late reply, but there are already glow in the dark cats, and there have been for years! though if the cat ate your glofish nothing would likely happen. Glowing cats had been made to study cancers and aids, but they aren’t out on the market.

  11. I just came across this youtube video which I remember seeing years ago. The interviewer asks, with a straight face, why if Glofish escaped to the wild, that they wouldn’t breed with bigger and bigger fish until all the fish in the sea glowed in the dark? Check it out:

    That, of course would not happen any more than sharks getting stripes from zebrafish or starting to taste like salmon, because they don’t breed with one another.

  12. Karl, there are already naturally evolved glowing fish – although they don’t use their own genes to glow. It’s usually a symbiosis with a micro-organism.

  13. Oh yes, and the genes for glowing mostly came from jellyfish and other aquatic animals. It’s not like the ocean is unprepared for glowing fish.
    Also, I just realized another level to how bizarrely anti-biological is the escape argument that the interviewer is making – zebrafish are freshwater fish and sharks are saltwater fish.

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