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    The GloFish is a trademarked brand of genetically modified (GM) fluorescent zebrafish with bright red, green, and orange fluorescent color. Although not originally developed for the ornamental fish trade, it is the first genetically modified animal to become publicly available as a pet.



Early development

The original zebrafish (Zebra danio) from which the GloFish was developed is a native of rivers in India and Bangladesh. It measures three centimetres long and has gold and dark blue stripes, and over 200 million have been sold in the last 50 years in the United States ornamental fish market. Despite the number of zebrafish sold, they have never established any reproducing populations in the United States, primarily because they are tropical fish, unable to survive in the temperate North American climate.

In 1999, Dr. Zhiyuan Gong and his colleagues at the National University of Singapore extracted the green fluorescent protein (GFP) gene from a jellyfish that naturally produced bright green bioluminescence. They inserted the gene into the zebrafish genome, causing the fish to glow brightly under both natural white light and ultraviolet light. Their goal was to develop a fish that could detect pollution by selectively fluorescing in the presence of environmental toxins. The development of the always fluorescing fish was the first step in this process. Shortly thereafter, his team developed a line of red fluorescent zebra fish by adding a gene from a sea coral, and yellow fluorescent zebra fish, by adding a variant of the jellyfish gene. Later, a team of Taiwanese researchers at the National University of Taiwan, headed by Professor Huai-Jen Tsai, succeeded in creating a medaka (rice fish) with a fluorescent green color.

The scientists from NUS and businessmen (Alan Blake & Richard Crockett) from Yorktown Technologies, a company in Austin, Texas, met and a deal was signed whereby Yorktown obtained the worldwide rights to market the GloFish. At around the same time, a separate deal was made between Taikong, the largest aquarium fish producer in Taiwan, and the Taiwanese researchers to market the green medaka in Taiwan under the name TK-1. In spring of 2003, Taiwan became the first to authorize sales of a genetically modified organism as a pet. One hundred thousand fish were reported sold in less than a month at US$18.60 a piece. It should be clarified that the fluorecent medaka are not GloFish, as they are not marketed by Yorktown Technologies, but instead by Taikong Corp under a different brand name.

Introduction to the U.S. market

The GloFish was introduced to the United States market in December, 2003 by Yorktown Technologies of Austin, Texas, after more than two years of extensive environmental research and consultation with various Federal and State agencies, as well as leading experts in the field of risk assessment. The definitive environmental risk assessment was made by the U.S. Food and Drug Administration (FDA), which has jurisdiction over all genetically modified animals, including fluorescent zebra fish, since they consider the inserted gene to be a drug. Their official statement, made on the 9th of December 2003, was as follows:

"Because tropical aquarium fish are not used for food purposes, they pose no threat to the food supply. There is no evidence that these genetically engineered zebra danio fish pose any more threat to the environment than their unmodified counterparts which have long been widely sold in the United States. In the absence of a clear risk to the public health, the FDA finds no reason to regulate these particular fish." [1]

Similar findings were reached by the State of California Department of Fish and Game and State of Florida Transgenic Aquatic Task Force.

Marketing of the fish was met by protests from a non-governmental organization called the Center for Food Safety. They were concerned that approval of the GloFish based only on a Food and Drug Administration risk assessment, would create a precedent of inadequate scrutiny of biotech animals in general.

To prevent this, the group, along with one of their sister organizations, filed a lawsuit in US Federal District Court to block the sale of the GloFish. The lawsuit sought a court order stating that the sale of transgenic fish is subject to federal regulation beyond the FDA's charter, and as such should not be sold without more extensive approvals. In the opinion of Joseph Mendelson, the Center for Food Safety's legal director:

It's clear this sets a precedent for genetically engineered animals. It opens the dams to a whole host of nonfood genetically engineered organisms. That's unacceptable to us and runs counter to things the National Academy of Sciences and other scientific review boards have said, particularly when it comes to mobile GM organisms like fish and insects. [2]

The Center for Food Safety's suit was dismissed on March 30, 2005.

Developments during 2006-2007

GloFish have continued to be successfully marketed throughout the United States. After more than three years of availability, there are no reports of any ecological concerns associated with their sale.

In addition to the red fluorescent zebrafish, trademarked as "Starfire Red", Yorktown Technologies released a green fluorescent zebrafish and an orange fluorescent zebrafish in mid-2006. The new lines of fish are trademarked as "Electric Green" and "Sunburst Orange", and incorporate genes from sea coral.[3] Despite the speculation of aquarium enthusiasts, it has been found GloFish are indeed fertile and will reproduce in a captive environment.[citation needed] However, the sale of any such offspring is restricted by US Patent number 7,135,613[citation needed].

As of January 2007, sale or possession of GloFish is illegal in California due to a regulation that restricts all genetically modified fish. The regulation was implemented before the marketing of GloFish, largely due to concern about a fast-growing biotech Salmon. Although the Fish and Game Commission declined to grant an exception (solely on ethical grounds) in December 2003, it later reversed course and decided to move forward with the process of exempting GloFish from the regulation. However, due to the State’s interpretation of the California Environmental Quality Act, Yorktown Technologies was informed by State attorneys that it would first need to complete an extremely expensive study, which could cost hundreds of thousands of dollars and take years to complete. According to the company’s web site, they have thus far declined to undertake this study. [4]

As of January 2007, Canada also prohibits import or sale of the fish, due to what they report is a lack of sufficient information to make a decision with regard to safety.

The import, sale and possession of these fish is not permitted within the European Union. On November 9, 2006, however, the Netherlands’ Ministry of Housing, Spatial Planning and the Environment (VROM) found 1,400 fluorescent fish, which were sold in various aquarium shops.[5]


  • "Troubled waters: fluorescent fish spark GM row" by A. Gumbel, May 4th, The Independent, London, England
  • "Frankenfish and the future", by F. Mazyoer, January 2004, Le Monde diplomatique (free in French, Esperanto, Portuguese and Japanese)
  • "Leuchtfische aus dem Genlabor", by M. Robischon, August 2006 Natürlich 8: 6 - 13
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "GloFish". A list of authors is available in Wikipedia.
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