They looked like small, swimming highlighters – like I had smoked something I shouldn’t have before going to this fish store.

After discussing fish for a week in America, I snuck out briefly to walk off long hours sitting in conferences and to see some fishy friends in the flesh. Inside a freezing Walmart, I saw my very first GloFish.

Glow up

They weren’t like the ones we had in the Philippines – usually poor Indian Glassfish (Chanda ranga) injected with fluorescent dye, or Blood Parrots (Amphilophus citrinellus plus Paraneetroplus synspilus) manually painted bright colours, which, at best, last a few months. The colors of the GloFish were totally unreal – and they seemed to be organically part of the fish. Even young ones gave a strong glow.

Over the past years, I’ve noticed more and more of them being sold en masse in Pinoy pet stores. Though relatively pricey at about PHP50 each compared to the average tetra or danio ouch-tag of PHP20, they can be even more colorful than saltwater fish, especially against a black background illuminated by blue LED lights.

Intrigued, I decided to do some research and found out that the creation of GloFish was actually pretty amazing, like a scaled-down version of the fictional Dr. Wu’s experiments for Jurassic Park.

It’s in the genes

The GloFish story began in 1999, when Dr. Zhiyuan Gong from the National University of Singapore was working on an environmental project to develop fish that would glow brightly in polluted water. His team inserted fluorescent jellyfish genes into the embryos of Zebra Danios (Danio rerio), creating glowing green fish. They immediately saw its game-changing potential for the aquarium trade.

Wild or neon? Albino or wild-type versions of fish were used to create the current strains of GloFish. The company behind GloFish now offers five fish species in six neon colors. (Altervista)

Soon, they created fluorescent red fish by inserting coral genes, then orange fish by adding a different jellyfish gene.

Today, millions of GloFish are available globally, with the genetically-engineered fish patented and sold by an American company called Spectrum Brands. From the initial three colors, GloFish are now available in six colors, including blue, pink, and purple – the fluorescent colors having been sourced from a vivid variety of coral, jellyfish, and sea anemone species.

The line of fish has also expanded. From just danios, GloFish terras, sharks, bettas, and barbs are now available, with the original stock sources from Black Skirt Terra (Gymnocorymbus ternetzi), Tiger Barbs (Puntius tetrazona), Rainbow Sharks (Epalzeorhynchos frenatum), and Fighting Fish (Betta splendens). Except for bettas, they’re all offered in a variety of colors. Only bright green bettas are currently available.

Though not originally developed for the ornamental fish trade, GloFish are among the first genetically-modified animals to be publicly accessible, with second and third generation fish bred and sold by hobbyists and fish farmers worldwide.

Cautious with curiosity

Though definitely magnificent – especially under actinic blue light – the creation of these fish breaks fresh ground. For thousands of years, people have selectively-bred plants and animals for certain characteristics. Goldfish are a good example of this, with the original drab fish looking nothing like today’s spotted, bubble-eyed, tripletail, balloon-shaped breeds. Many dog breeds such as Bulldogs and Chihuahuas look nothing like the loping wolves of prehistory.

Brazen but brilliant. Zebra Danios, Black Skirt Tetras and Tiger Barbs are just some of the fish which have been genetically-modified to glow. They are best cared for in dim tanks lit by blue LED lamps. (GloFish)

Unlike selectively-bred animals, GloFish were created by combining the genes of two animals which belong to different phyla. Though the risk of them becoming invasive isn’t too high (bright colors are usually eat me signs for birds and carnivorous fish), we should rightfully be wary of them and their potential effects on our remaining rivers and lakes.

With the new science of transgenesis propelled by newfound profit from GloFish, what comes next? Will our sons and daughters someday keep neon blue cats, glowing orange rabbits or designer green dogs? Who knows? But if it’s so, then the future will certainly look bright.

This appeared in Animal Scene magazine’s September-October 2020 issue

You might want to read:
– Is the heat killing the fishes?
– Seeing red: Dominant red-colored fishes
– Extendable fish ponds