What exactly are GloFish?


No doubt you’ve come across a tank or two in a local fish store (LFS) or box chain like PetSmart of neon fish under a black light. These bright fish are called as GloFish and are sure to capture your attention, but why exactly to they glow and are they just like other fish we see?

The short answer to this question is, yes they are similar to other fish we see in the aisles, but these unique fish are genetically modified to fluoresce. They are completely safe to own and make for a different look altogether from the typical aquarium setup.

Where did the story of the GloFish begin? In 1999 scientists in Singapore were looking for a way to detect toxins in polluted water ways. The thought was to see if these fish could be harnessed to change colors due to toxins in the water to protect the local communities.

GloFish started out when scientists took the green fluorescent protein gene found in jellyfish and were able to insert this gene into a zebrafish embryo. The end result was a fish that brightly fluorescent under both natural white light and ultraviolet light.

After this key breakthrough, the team uses a gene from coral to produce a line red fluorescent zebra fish and orange-yellow fluorescent zebra fish, by adding a variant of the jellyfish gene.

After this the scientists met Yorktown Technologies, a company from Austin, Texas. Yorktown saw the potential for this fish in the ornamental trade and bought the rights to market the fish giving birth to the “GloFish” brand.

The first fish release by Yorktown was the red variant of the zebrafish they dubbed the Starfire Red Danio in 2003. Today there are 12 lines of fish in the GloFish family, a combination of both species and colors.

Of course there was some hesitation on bringing genetically modified fish into the U.S. marketplace. After a few regulatory hurdles, we started to see the GloFish appear in stores here. A last major hurdle was cleared when California allowed the sale of GloFish in 2015.

Many were concerned that these fish could impact local populations of fish and create mutant strains. We have seen other invasive fish, like goldfish and Plecostomus, take over local environments devastating native populations of wildlife along the way.

However, these tropical strains would have a hard time surviving and if they did, the bright colors would make them hard to hide, making them a prime target for larger predators.

Today, there are six colors of GloFish including the original Starfire Red, others include Cosmic Blue, Electric Green, Galactic Purple, Sunburst Orange and Moonrise Pink. The fish species include danios, tetras and barbs.

Having a GloFish may not be for everyone, but they are quite striking under a blue or black light making them appealing to kids. Overall, the care of GloFish is just like other fish of the same species and make a great starter fish to work with.

There is also a full line of GloFish products made specifically for a bright and fun environment including aquariums (although any aquarium will do, you will just want to make sure you have a blue light to maximize the glow), lights and decor.



  1. Hi love the colors we are getting a 10 gal tank of glowfish and it is going to be cool
    How can you tell males from females


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