If you actually read the page about glofish you will see that they were not genetically modified to create interesting pets but were modified for the sake of science. http://www.glofish.com/
To take a passage directly from the glofish website
"GloFish™ fluorescent fish are beautiful and unique fish that were originally bred to help detect environmental pollutants. It was only recently that scientists realized the public's interest in sharing the benefits of this research. GloFish™ fluorescent fish are safe for the environment and make wonderful pets for new hobbyists and experienced enthusiasts alike."