This months profile was written by Chris an active contributor to the site.







    1. Genetically altered from the ever-popular Zebra Danio, GloFish® were originally created to aid in waterway testing and gene research. By combining a naturally occurring fluorescence gene found in anemones, with the hardy and energetic Zebra Danio, scientists sought to efficiently determine whether or not waterways had become polluted by following the health and glow of these little beacons. Eventually, they realized there was a strong public interest in this beneficial research, which lead to commercial sales of fluorescent GloFish. Around the world, scientists continue to work with these fluorescent fish in protecting the environment and developing new disease-fighting drug therapies.
    Fluorescent Zebra Danios have existed for over a decade, and a portion of the proceeds from direct sales have gone toward furthering the genetic research through which they were created. This has brought additional breakthroughs in molecular biology, vertebrate development, understanding cellular disease, as well as cancer and gene therapy.

Quick stats:

Listed tank sizes are the minimum
Size: Up to 2in (5.5cm).
Tank: 30in + (15gal +).
Strata: Generally upper and mid-level.
PH: 6.8 – 7, tolerates wide range.
Hardness: Soft to moderately hard (0 to 18°DH)
Temperature: 72°F to 80°F (22°-27° C)

Classification of wild stock:

Order: Cypriniformes (carps)
Family: Cyprinidae
Genus: Brachydanio
Species: rerio

Common name:



Distribution of wild stock:


     India to Bangladesh.

General Body Form:

    The GloFish was created by combining Zebra Danio genes with those of a certain luminescent anemone to emit a bright neon glow. With the same long and slender body, it retains the classic fish shape of Danios. There are really no differences genetically or behaviorally between GloFish and Zebra Danios. Their mouth still angles upward slightly, with the same two sets of barbels. While female GloFish continue to grow larger with a more rounded belly, in general.


    GloFish were originally altered to emit a bright pink color; however green, yellow and orange coloration’s have since been created and bred. The glowing coloration of the GloFish will never fade or change, as it remains within their genetic structure, and will actually be passed on to their offspring should they spawn. The fry would have the same color of one of the parents, and some combinations of colors have been found. It is recommended that a strong light be kept on during daylight hours, and replaced by a black-light at night in order to see them “glowing” at their best. Though GloFish do require varying amount of light and darkness, like any other fish, so be sure not to leave the lights turned on overnight. GloFish were originally available in three official colors: Starfire Red, Electric Green, and Sunburst Orange.


The original Zebra Danio.


    Having been originally from varying Asian regions, and altered in laboratories, GloFish flourish in waters similar to their relative Zebra Danios. They are extremely active, always racing around and providing a spectacle. An ideal tank would be at least 30in. (76.2cm) in length, decorated tank with plants and rockwork; however one should also leave plenty of room for swimming. They eat all types of commercial food: live, flakes, and frozen. They are a low maintenance and hardy species that do not require extremely precise water conditions. Because of this, GloFish also make the ideal fish for the cycling a tank.

Biotopeof wild stock:

    Zebra Danios, found in fast flowing streams, tend to enjoy wide-open spaces around mid to upper water-level. So too do GloFish. They also do very well in community tanks with like-minded fish. They are strictly tropical freshwater fish and are unsuited for cool, non-tropical environments. GloFish can exist in a fairly wide temperature range of 64-86°F (18–30°C), but temperatures of 72-80°F (22-27°C) are much preferred. This will most likely demand a heater in the tank in order to maintain a consistent warmer climate. It is crucial that one avoid drastic temperature changes, as that is stressful, and can be fatal to any fish. Like Zebra Danios, GloFish are schooling fish which should ideally be kept in groups, though not overcrowded. And never keep any solitary fish in a small bowl without circulation and filtration.


    GloFish can be very easy fish to breed should your tank meet certain requirements. Provide the best food possible, a low stress and clean environment, as well as a separate tank for the process (Preferably 5-10 gallons) if possible. Lay gravel or marbles on the tank floor, and keep the water level low to prevent the fish from eating the eggs as soon as they lay them. Introduce several conditioned GloFish into the tank to ensure both male and female fish are included. After the spawning has ended, the marbles will protect the eggs that were laid as they sink between the marbles. Remove the adult fish from the breeding tank, and the eggs should hatch after a day or two. Once the fry are swimming they can be fed finely ground flakes, paramecium, inforusia or commercial liqui-fry. Today, GloFish found in stores and online have been bred from the offspring of the original fluorescent Zebra Danios. The remarkable colors of each GloFish are inherited from the parents, remain throughout their lifetime, and passed on to their fry.


    GloFish have been analyzed and reviewed by the U.S. Food & Drug Administration, which has jurisdiction over biotech animals, United States Department of Agriculture and United States Fish & Wildlife Service, all of which found no evidence that fluorescent fish pose any more threat to the environment than wild-type Zebra Danios. In addition to the Federal review, GloFish have since been reviewed by state agencies such as the State of Florida Transgenic Aquatic Species Task Force, and the California Department of Fish & Game.

Google Photos
Zebra Fish as Pollution Indicators


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