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.

Later, a team of researchers at the National Taiwan University, headed by Professor Huai-Jen Tsai, succeeded in creating a medaka (rice fish) with a fluorescent green color, which, like the zebrafish, is a model organism used in biology.

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.

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.

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.

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.

The colors are trademarked as "Starfire Red", "Moonrise Pink", "Sunburst Orange", "Electric Green", "Cosmic Blue", and "Galactic Purple".

Despite the speculation of aquarium enthusiasts that the eggs of the fluorescent fish were pressure treated to make them infertile, it has been found some GloFish are indeed fertile and will reproduce in a captive environment.

The regulations were lifted in 2015 due to a growing body of evidence and the findings of the Food and Drug Administration and the Florida Department of Agriculture and Consumer Services.

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.

Some retailers opted not to stock the fish due to low trust in federal agencies to properly regulate the organisms.

[18] According to the mating trials that were analyzed in the study, wild-type males sired twice as much as the genetically modified fish due to their more aggressive nature.