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GloFish Shark Care Guide | GloFish Care Guide Series Ep. 5 | Rainbow Sharks

About the GloFish Shark

Not actually a shark at all, but more closely related to carp or minnows, these fish do have an uncanny resemblance to true sharks. The GloFish shark is the genetically modified version of the rainbow shark, also known as the red finned shark, and even with the new coloration

of the body, they still seem to retain their bright red fins.

These fish are very popular in the aquarium trade and are considered to be quite hardy, but can be difficult to keep, as they are the largest of the GloFish getting up to 6 inches in size, and they can be very territorial towards other fish. But with the right care and set up these fish can live as long as 8 years.

Tank Set Up

Because of their territorial nature and high energy, the minimum tank size recommended for keeping just one of these fish is a 50 gallon long.

If you wish to keep more than 1 the recommended size is 125 gallons for them to peacefully coexist. That

being said, the bigger the tank, the better. GloFish sharks are much more likely to become aggressive if they are kept in too small of a tank.

You will also want to give these fish plenty of hiding spaces using plants and decorations, and they prefer to have a sandy substrate. Because they are used to fast moving waters, you will also want to invest in a good filter with higher flow.

These fish are used to warmer waters, so you may or may not need to use a heater as the temperature range for them is between 75°-81°F. They also prefer soft to fairly hard neutral waters with a pH between 6.5-7.5.

Tank Mates

When choosing tank mates for GloFish sharks or rainbow sharks you will want to keep in mind that they are considered bottom dwellers and are known to be very territorial, so you will want to avoid keeping other bottom dwellers such as red tailed sharks or catfish.

Instead you will want to choose top or mid dwelling species that can defend themselves if needed. These fish are typically seen kept with species such as barbs, danios, gouramis, and rainbowfish.


Rainbow sharks are omnivores and primarily bottom feeders. They will readily accept high quality sinking pellet foods and algae wafers. These fish also love feeding on brine shrimp, bloodworms, and daphnia.

While they will feed on some algae in your tank it is also a good idea to feed them some vegetables such as blanched zucchini, cucumber, or spinach.


Rainbow sharks are an egg laying species and are often considered to be difficult to breed in the aquarium, due to their territorial nature, it can be difficult to keep multiple rainbows in the same tank.

It can also be difficult to tell male and female sharks apart until they reach maturity, or around 4 inches in size. Male rainbow sharks will have thinner bodies than females along with black lines along the tailfins. Males also tend to be more vibrant in color.

But as with all GloFish species though, there is a patent on them, so while you may attempt to breed them in your home aquarium, you cannot legally sell them.

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