Galaxy Rasbora – Habitat, Care, Feeding, Tank Size, Breeding

The Galaxy Rasbora was discovered in 2006 in Myanmar’s Salween basin. It is a relatively recent addition to the aquarium world, and it has attracted fish-keepers due to its striking coloration.

The name of the fish has since been changed to the Celestial Pearl Danio since it is closely related to the danio species.


The galaxy rasbora has an unusual body when compared to that of its close relatives. Its body length is around three times its height with a stumpy nose. It mostly reaches 1 inch in length from head to tail.

The galaxy rasbora has sexual dimorphism, where the males and females exhibit different body coloration. The males have more vibrant colors on their bright blue bodies while the bodies of the females have a bluish-greenish background hue with a tint of yellow on the belly.

Courting males will exhibit a rich deep coloration on their bellies. The bodies of both sexes have small dots running across them, and the transparent gill plates make it possible to see the blood vessels.


The galaxy rasbora inhabits small ponds in Salween River Basin in the Shan Plateau. These ponds are populated with a wide variety of aquatic plants, and they enjoy full sun exposure. The ponds are slightly alkaline, and the temperatures mostly stay below 75 °F.


The galaxy rasbora feeds on plants, algae, and zooplankton in the wild, and they will supplement this diet with small invertebrates and worms.

In an aquarium, the fish will accept dried foods like flakes, pellets, and granules, which should be small enough to fit in their mouths. Sinking pellets are ideal because the fish roam at the bottom part of the aquarium.

Aquarists also give the galaxy rasbora live or frozen food, including brine shrimp, Daphnia, tubifex, krill, and grindal worms. Cycle the menu regularly to make the fish more vibrant.

Water & Tank Requirements

Now, let’s take a look to the galaxy rasbora water conditions and tank requirements.

Tank Size

Do not use anything less than a 10-gallon tank to keep the galaxy rasbora. You should aim for two gallons per fish, and you can keep six of them in a 20-gallon aquarium. The fish do not require a lot of space, although individuals can be seen in their own separate spots.

Temperature and PH

The ideal temperature for galaxy rasbora is between 73-79 °F. You can use a heater to keep the temperature in this range as well as a thermometer to keep track of any changes. The recommended PH is 6.5 to 7.5, while the hardness should be soft to medium.


If you have a 10 to 20-gallon tank, you can either use a sponge or hang-on-back filter. Sponge filters do not disturb the flow of the water, while hang-on-back are more effective at filtration. You should also use a pre-filter sponge to ensure the fish do not get sucked in the filter.


The galaxy rasbora can be kept in dimmed or bright light. You can use LED or fluorescent fixtures, which will also depend on the aquatic plants you have. The lighting should reach the tank’s bottom, and you can use a shallow one to achieve this.


The fish will thrive in a densely planted tank, and you can use sprawling species to provide a safe habitat for them at the bottom of the aquarium. Common plants include the Amazon Sword, chain swords, and jungle val.

The galaxy rasbora is not known to dig through the substrate, and any type will be okay. You can use sand or gravel and include driftwood and pebbles to mimic a natural environment.


The fish thrive in groups of five to six. Male galaxy rasboras can get aggressive with other males, and you can keep females if you desire a peaceful community tank. If you keep males and females together, provide many hiding spots, and aim for a healthy ratio. Galaxy rasboras are shoaling fish, and you will mostly see them hanging close to each other.

The fish are shy in nature, and you should keep them with equally peaceful and small fish. You can couple them with guppies, neon tetras, small Corydoras catfish, chili rasboras, and Angelfish. Do not keep your galaxy rasboras with fish that will bully them.


The galaxy rasboras lay eggs via sporadic spawning as they have no breeding season. As long as the water conditions are ideal and they are feeding well, the chances are that they will reproduce in the aquarium.

You can utilize a separate breeding tank that has a bare bottom for maximum hygiene. The tank can be as small as 30 × 20 × 20 cm with a temperature of 24 °C. While the parents do not necessarily require extra conditioning, you should prepare them by offering a wide variety of live and frozen food.

Equip the tank with a spawning mop that mimics aquatic moss and use a filter to keep the levels of ammonia and nitrates under control. You can also use fine-leaved plants like Elodea and Hornwort to catch the eggs.

Introduce two females and a single male in the tank and leave them for about five days. The males can be seen dancing around the females and displaying their rich coloration. The male leads the female to the spawning mop and encourages her to lay eggs that he will fertilize soon after. This process goes on over a number of hours.

The females can lay as many as 30 eggs at a time, although fish keepers commonly get 12 of them. The eggs incubate for two to four days, and they subsequently progress to the larval stage and learn how to swim.

The fry feeds on their yolks for the first three days, after which they can be given small foods. You can provide them with powdered food, flakes, or infusoria. Be keen not to overfeed the small galaxy rasboras and move them to the main aquarium once they resemble small adults.


Galaxy rasboras will make a colorful addition to a community aquarium. Their grouping nature and calm demeanor make them suitable tankmates for small and peaceful fish like neon tetras and guppies.

Galaxy rasboras also have low demands when it comes to tank maintenance. As long as the water conditions are ideal and they have hiding spots, they will thrive in any setup.

Updated: February 18, 2020

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