The GloFish is a patented and trademarked brand of genetically modified fluorescent fish. Various GloFish are currently on the market. Zebrafish were the first GloFish that were available within pet stores and are now sold in bright green, red, orange-yellow, blue, and purple fluorescent colors. Recently, Electric Green, Sunburst Orange, and Moonrise Pink colored tetra (Gymnocorymbus ternetzi) and Electric Green tiger barb (Puntius tetrazona) have been incorporated to the lineup. Although not originally developed for the ornamental fish trade, it’s one of the first genetically modified animals to become publicly available for a pet. It is only sold in the United States where it has remained the only genetically modified pet to be publicly available. The rights to GloFish are owned by Yorktown Technologies, the company that commercialized the fish.

The original zebra fish, from which the GloFish was developed, is native to the rivers of India and Bangladesh. It measures three centimeters long and has gold and dark blue colored stripes. More than 200 million have been sold in the last 50 years within the United States ornamental fish market. In spite of the number of zebra fish sold, they have never established any wild populations within the US, mostly due to tropical fish being unable to survive in the temperate North American climate.

GloFish were introduced into the US market in late 2003 by Yorktown Technologies, after more than two years of extensive environmental research and consultation with a variety of Federal and State agencies, as well as leading experts within the field of risk assessment. The defining environmental risk assessment was made by the US Food and Drug Administration, which has jurisdiction over all genetically modified animals, including fluorescent zebra fish, since they consider the inserted gene to be a drug.

Marketing of the fish was met with 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 establish a precedent of inadequate scrutiny of biotech animals in general. In order to prevent this, the group, in addition to one of its 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. This lawsuit was found to be without merit and dismissed on March 30, 2005.

The GloFish have continued to be successfully marketed throughout the United States. Since their introduction in late 2003, there have been no reports of any ecological concerns associated with the marketing of these fish.

In addition to the red fluorescent zebra fish, trademarked as Starfire Red, Yorktown Technologies released a green fluorescent zebra fish and an orange-yellow fluorescent fish in mid 2006. In 2011, purple and blue fluorescent zebra fish were released.

In spite of the speculation of aquarium enthusiasts that the eggs are pressure treated to make them infertile, it has been found that some GloFish are indeed fertile and will reproduce in a captive environment. However, the GloFish Fluorescent Fish License states “Intentional breeding and/or any sale, barter, or trade, of any offspring of GloFish fluorescent ornamental fish is strictly prohibited”, therefore imposing a legal GURT.

The sale or possession of GloFish remains illegal in California because of a regulation that restricts all genetically modified fish. The regulation was implemented before the marketing of GloFish, largely because of the concern about a fast-growing biotech salmon. Although the Fish and Game Commission declined to grand an exception in December 2003, it later reversed course and decided to move forward with the process of exempting GloFish from that regulation. However, because of the State’s interpretation of the California Environmental Quality Act, Yorktown Technologies was informed by State attorneys that it would first need to complete a study which could cost hundreds of thousands of dollars and take years to finish. According to the company’s web site, they have thus far declined to undertake this study.

Canada prohibits the import or sale of the fish also, because they report 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 found 1,400 fluorescent fish, which were sold in a variety of aquarium shops.

In January of 2009, the U.S. Food and Drug Administration formalized their recommendations for genetically engineered animals. These non-binding recommendations explain the way in which the FDA regulates all GM animals, including GloFish.

Image Caption: GloFish fluorescent fish. Genetically modified. Danio rerio. Credit: