Teaching an old fish new tricks

By Hannah Scutter BSc

When training aquatic animals many people will think of dolphins and orcas, but rarely small aquarium fish. However, there are a few well known aquarium species that have been seen to learn to do just that. Species such as cichlids, in particular Oscars (Astronotus ocellatus), betta fish and even gold fish have been taught tricks by their owners. With a combination of operant conditioning, positive reinforcement, lasers and clickers these training triumphs have been achieved. Supported by videos on Youtube, various blogs and facebook pages tricks such as swimming through hoops and playing fetch have been catalogued. In one such case a small aluminium foil ball was placed into an aquarium and a fish was shown to move the ball in front of its filtration pump in order for it to be then catapulted around its tank. This ball was then chased, caught and taken back to the filtration pump for round two. Colour recognition has also been expressed through similar learning styles.

A growing interest in such fishy fun has meant that there are now courses and kits available online to help others in their training adventures.

Perhaps we should all give our fish the chance to interact with us more often.


Considering the GloFish

By Stefania Unips

The GloFish is a trademarked transgenic (genetically modified) fluorescent fish. This article leaves aside the ethics of GM technologies and looks into all relevant elements regarding fish well-being irrespective of the fishes’ nature.

The first GloFish were zebra danios (Danio rerio) and later on black widow tetras (Gymnocorymbus ternetzi) and tiger barbs (Puntius tetrazona) were added to the collection. Originally developed to help detect water contaminants by becoming fluorescent in the presence of a pollutant [7], GloFish were first sold as pets in the US in 2003 [10]. They are neither dyed, nor injected, but have been added a naturally occurring fluorescent gene that they pass to their offspring. While the red variety contains a gene that is found in sea anemones, the green GloFish have the jelly fish to thank for their vibrant colour [1]. Even though GloFish sold exceptionally well [1], controversy over this scientifically engineered pet prompted the American Food and Drug Association (FDA) to issue a statement which concluded that the fish do not pose a direct threat to the food supply on the basis that tropical aquarium fish are not used for food purposes [2]. Other independent agencies, such as the Florida Division of Aquaculture [3], as well as a number of studies, have also declared GloFish safe for the environment. Concerns that GloFish could become invasive or have an edge over wild-types when it comes to attracting a mate have been dismissed. According to Alan Blake, the CEO of Yorktown Technologies, the company that produces these genetically modified organisms, GloFish are less ecologically fit than wild-types [6]. Bill Muir, who is a professor of genetics at Purdue University, has reviewed the data provided by Alan Blake [4]. He is not tied to the “product” and worked for free to conclude that “one would expect natural selection to eliminate the trans gene regardless of where it escaped or was released.” Moreover, if the fish ever did find freedom in freshwaters, their glow would make them vulnerable to predators [5].

Alan Blake insists that Yorktown Technologies is committed to humane breeding practices. The fluorescent fish used in research did not exhibit any signs of stress and their life-expectancy is unchanged. He also argues that the presence of GloFish on the market has reduced the sales of dyed and injected fish and that after 12 years of GloFish business the initial safety assessments have been confirmed [6]. The company donates money to support organizations engaged in providing clean water to poor regions in Africa, initiative that serves 20 000 people, and offers free, educational materials that teach children and teenagers about basic fish keeping practices, genetics and biology.

Yorktown Technologies is fairly honest about the manufacturing process of its novelty product and provides proper information about GloFish care. Customers are advised to consult with local fish store experts before starting a new aquarium or adding fish to a community tank and the company recommends that the fish be treated with the utmost care [7].

So where is the problem? The manufacturer’s efforts are genuine and have most certainly changed human and fish lives, but obvious positive results should not cover up potential mistakes. For example, despite advertising some suitable equipment such as air pumps and filters (which according to some customer reports cause death by suction), the company also sells plastic plants with sharp edges that may harm the fish and flashy gravel and ornaments that create an artificial environment. If GloFish are “exactly the same in terms of care, including everything from general care and temperature preferences to water quality and nutritional needs” [7] as their less radiant counterparts shouldn’t they be kept in a tank that replicates their natural habitats? These vary from flowing streams with rocky substrates to mature rice paddies and it appears that the fish thrive in a heavily planted setup [8]. Moreover, if the “one inch of fish per gallon” (1 gallon = 4.546 litres) rule of thumb applies, one 2-inch adult GloFish would need roughly 9 litres of water. If we take into account that Danios, Tetras and Barbs are sociable fish that should be kept in groups of about 6-8 individuals [9] and that the fish do reproduce if certain conditions are met, how appropriate are 8 litres or even 23 litres aquarium kits? Fry could be given away to make room for the existing tank occupiers, however “intentional breeding and/or any sale, barter, or trade, of any offspring of GloFish fluorescent ornamental fish is strictly prohibited”, according to the GloFish license notice [7].

Yorktown Technologies pays a lot of attention to the way it promotes its’ invention. Beginner aquarist and children are encouraged to “Experience the Glo” through videos, comics and even a GloFish app and on October 1st 2014 two new kinds of GloFish, Starfire Red and Cosmic Blue Tetras saw the light of day. It is unclear if GloFish are treated as living organisms with specific needs or rather as classic products whose retail success depends on the producer’s marketing strategies. “They’ve got great colour. People are tired of seeing the same thing in the pet store all the time. It’s adding a bit of excitement to the industry” declared a GloFish trader to the BBC [1]. One blogger adds that GloFish have the potential to replace marine species that are much more difficult to care for. Aquarists could benefit from the bright colours that are normally exhibited by saltwater fish with reduced effort in terms of tank and equipment requirements [10].

There are over 180 species of fluorescent fish in nature [11]. The fluorescent gene is used to study skin and prostate cancer [12], [13] and GloFish serve a valid research and educational purpose. At present, GloFish are banned from Europe, Canada and Australia [7], but in the US it appears that these fish are sold as pets with the most obvious purpose of adding novelty to the hobby. Even though in theory they should be able to live normal, fishy lives, in practice, the tank is leaking.


[1] http://news.bbc.co.uk/1/hi/sci/tech/3660289.stm (accessed 10th April 2016)

[2] http://www.fda.gov/animalveterinary/developmentapprovalprocess/geneticengineering/geneticallyengineeredanimals/ucm413959.htm (accessed 10th April 2016)

[3] http://www.sptimes.com/2004/02/01/news_pf/Opinion/Glowing_wild.shtml (accessed 10th April 2016)

[4] http://www.the-scientist.com/?articles.view/articleNo/15391/title/Glofish-Gives-New-Shine-to-GM-Debate/ (accessed 10th April 2016)

[5] https://www.nextnature.net/2012/09/why-its-time-to-calm-down-about-invasive-gm-glofish/ (accessed 10th April 2016)

[6] http://nas-sites.org/ilar-roundtable/files/2015/11/BLAKE-NAS-ILAR-Roundtable-Presentation-Alan-Blake.pdf (accessed 10th April 2016)

[7] www.glofish.com (accessed 10th April 2016)

[8] http://www.seriouslyfish.com/species/ (accessed 10th April 2016)

[9] http://www.aquaticcommunity.com/fish/scientific/ (accessed 10th April 2016)

[10] http://www.biofortified.org/2012/09/are-glofish-bad-for-the-environment/ (accessed 10th April 2016)

[11] http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0083259 (accessed 10th April 2016)

[12] http://phys.org/news/2010-01-fluorescent-fish-gene-function.html (accessed 10th April 2016)

[13] http://cancerres.aacrjournals.org/content/67/23/11386.full (accessed 10th April 2016)