Have you seen the bright, neon-colored fish at the pet store and wondered what they are? GloFish® are an extremely popular fish among beginners because of their stunning rainbow colors, energetic behavior, and resilient ability to live in a wide range of water conditions. Find out how they got their fluorescent glow and how to care for them so they live a long and healthy life.
What are GloFish?
GloFish are not just one type of fish but rather a collection of freshwater species that have been genetically modified with fluorescent protein genes that naturally occur in jellyfish, sea anemones, corals, and other marine life. They were originally developed by scientists to study genetics and help detect certain pollutants in the water, but their dazzling appearance made them a popular addition to the aquarium fish industry. These special fluorescent genes cause the GloFish to vibrantly glow under blue light and does not appear to impact their quality of life.
Currently, GloFish are available in the following options, but more varieties and colors are being developed on a regular basis.
- Zebra danios (Danio rerio)
- Black skirt tetras (Gymnocorymbus ternetzi)
- Tiger barbs (Puntius tetrazona)
- Rainbow shark (Epalzeorhynchos frenatum)
- Betta fish (Betta splendens)
The husbandry for each species varies slightly, but in this article, we will try to generalize their care requirements.
GloFish tetras are genetically modified black skirt tetras that glow under blue lighting.
What are the colors of GloFish? Currently, they come in Moonrise Pink, Starfire Red, Sunburst Orange, Electric Green, Cosmic Blue, and Galactic Purple.
Are GloFish injected with dye? Because they are not injected with dye, their brilliant coloration is a hereditary trait that is passed on from parent to offspring.
Is it illegal to breed GloFish? GloFish are trademarked and patented by GloFish LLC, so only they and their affiliates are legally allowed to breed and sell them. If your fish accidentally reproduce in your home or school aquarium, it is not a problem. However, the sale, barter, or trade of GloFish offspring by hobbyists and other unlicensed entities is strictly prohibited.
What is the lifespan of a GloFish? It depends on the species, but on average, these fish live approximately 3-5 years. Betta fish tend to have a short lifespan closer to 2-3 years, whereas some hobbyists have reported owning rainbow sharks up to 13 years.
How much do GloFish cost? GloFish tend to cost more than their normal-colored counterparts. At the time of this article, they range in cost from $6.49 for a GloFish danio to $24.99 for a premium male GloFish betta.
How Do You Set Up a GloFish Aquarium?
Most GloFish aquarium kits are quite small, where 10 or 20 gallons seems to the biggest size that is available at mainstream pet stores. However, most GloFish are very active and need to be kept in 20- to 40-gallon aquariums or larger. Also, the blue light that comes with GloFish tanks does not grow aquarium plants very well, which means you may need to add lots of aquarium decorations and fake plants to prevent any aggression among your fish.
GloFish still look very colorful under normal white light and would do well in a beautiful planted aquarium.
A smaller fish tank with no plants will require lots of water changes and filter maintenance to make sure your fish are not living in water polluted by their own waste. (Since the waste chemicals are clear in color, use water test strips to determine how dirty your water is and if it’s time for a tank cleaning.) If possible, buy a bigger aquarium that is not specifically for GloFish. It will work fine as long as it has a white light setting and “moonlight” setting that gives off blue light. Then you can add low light aquarium plants that grow under white light during the daytime and naturally consume the toxic nitrogen chemicals produced by your fish’s waste. A larger fish tank filled with lots of plants will help keep the water cleaner and your fish healthier overall.
Should I turn off my GloFish light? Yes, do not leave the blue light on for 24 hours a day because the fish need to sleep in the dark at night and algae can grow if you turn on the aquarium light more than 12 hours a day. If you find that your fish tank is experiencing green water or excessive algae growth, use a power outlet timer for the aquarium light and number the amount of hours the light is on each day.
Do you need a heater for GloFish? All GloFish except for the danios need a heater because they are tropical fish that require temperatures of approximately 75-80°F (24-27°C) to stay healthy. If you keep them at a room temperature of 68-72°F (20-22°C), the continuous stress of being too cold can cause them to get sick. A simple aquarium heater will automatically take care of the temperature for you.
How many GloFish should be kept together? Danios, tetras, and barbs are schooling fish, so you should get at least six of the same species to make them feel more comfortable and lessen aggression problems. Different colors are fine, so you could, for example, get one tetra of each color to form a school of six. Tiger barbs are a semi-aggressive fish that may attack other types of GloFish, so if you are a beginner fish keeper, we highly recommend that you keep them in a species-only tank that just contains other tiger barbs.
GloFish danios are a fast-swimming schooling fish that get along with other peaceful, community fish.
Rainbow sharks grow up to 6 inches (15 cm) long and can be a bit territorial, so we only recommend getting one for a 29-gallon or larger aquarium. Betta fish are also semi-aggressive and won’t do well with the other types of GloFish, so we recommend just getting one for a 5-gallon fish tank or bigger. If you are looking for tank mates to potentially keep with betta fish, see our recommendations here.
What do GloFish Eat?
Fortunately, Glofish are very easy to feed and would love it if you provided them a diverse variety of nutritious foods to eat, such as flakes, pellets, frozen foods, and gel food. Betta fish might be the only caveat because they do prefer to eat from the water surface, so try feeding them floating betta pellets, freeze-dried foods, and frozen foods.
Feed different kinds of fish foods each week to ensure that your GloFish get all the essential nutrients they need for optimal health and coloration.
Are GloFish Hard to Keep Alive?
The developers of GloFish deliberately chose the hardiest, most beginner-friendly species possible to make GloFish, so in general, they are fairly bulletproof as long as you keep their aquarium clean and feed them well. However, newly purchased GloFish are sometimes underweight and stressed out, which makes them more susceptible to illnesses. Try to choose GloFish that are swimming well, have slightly rounded bellies, don’t exhibit any symptoms (e.g., ripped fins or white spots), and are not otherwise behaving oddly. We recommend quarantining all new fish that you bring into your home to prevent the potential spread of disease to your aquariums and to treat them more easily with medication if needed. Also, make sure to keep them in larger aquariums of at least 5 gallons for a betta fish, 20 gallons for tetras and danios, 30 gallons for tiger barbs, and 30-40 gallons for a rainbow shark.
Best of luck with your new GloFish. Our Aquarium Co-Op retail store does not sell GloFish because we believe there is already a huge variety of colorful fish in nature to choose from. To order aquarium fish online, check out our recommended fish sellers below.