GLoFish - The First Genetically Modified 'Pet'

The GloFish is a patented 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.

The original zebrafish (Danio rerio) from which the GloFish was developed is a native of rivers in India and Bangladesh. It measures three centimeters 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 were working with a gene called green fluorescent protein (GFP), originally extracted from a jellyfish, that naturally produced bright green bioluminescence. They inserted the gene into a zebrafish embryo, allowing it to integrate into the zebrafish's genome, which caused the fish to be brightly fluorescent 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 (蔡懷禎), 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, L.P., 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 fluorescent medaka are not GloFish, as they are not marketed by Yorktown Technologies, but instead by Taikong Corp under a different brand name.