I’m not sure where you read that, but that is incorrect:
“The original
zebrafish (or zebra danio, Danio rerio) is a native of rivers in
Indiaand
Bangladesh. It measures three centimeters long and has gold and dark blue stripes. In 1999, Dr. Zhiyuan Gong
[2] and his colleagues at the
National University of Singapore were working with a gene that encodes the
green fluorescent protein (GFP), originally extracted from a
jellyfish, that naturally produced bright green
fluorescence. 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 constantly fluorescing fish was the first step in this process, and the National University of
Singapore filed a patent application on this work.
[3] Shortly thereafter, his team developed a line of red fluorescent zebra fish by adding a gene from a sea
coral, and orange-yellow fluorescent zebra fish, by adding a variant of the jellyfish gene. Later, a team of researchers at the
National Taiwan University, headed by Professor Huai-Jen Tsai (蔡懷禎), succeeded in creating a
medaka (rice fish) with a fluorescent green color, which, like the zebrafish, is a
model organism used in biology.”
(
https://en.m.wikipedia.org/wiki/GloFish)
As you can see, they were
not made by accident. They were created on purpose, and I just think it’s cruel. The original fish is beautiful, and shame on anyone who says otherwise.