Celestial Pearl Danio (Galaxy Rasbora) – Size, Tank Mates, Breeding & More [Care Guide]

The celestial pearl danio is a popular peaceful freshwater fish. Find out about size, tank mates, breeding, and much more in this extensive care guide.

Celestial Pearl Danio – Quick Facts

In a rush? Check out the quick facts about Celestial Pearl Danio below.

Fish Info

Scientific NameDanio margaritatus
Common NamesCelestial Pearl Danios, Galaxy Rasboras, Danio Margaritatus
AppearanceThe Celestial Pearl Danio is a small, slender fish with off-white spots resembling tiny pearls. It is about 1 inch (2.5 cm) in length.
DifficultyCelestial pearl danios are not difficult to care for.
DistributionThe fish is found in Myanmar, Thailand, Laos, and Cambodia.
LifespanThe lifespan of a Celestial Pearl Danio in an aquarium is about two years.
TemperamentThe celestial pearl danio is a peaceful fish.
Keep in Groups ofA group of at least six should be kept together.
Tank MatesGuppies, Endlers Guppy Fish, Zebrafish, Neon Tetra, Cherry Barb, Red Cherry Shrimp, Amano Shrimp, Bamboo Shrimp, Ghost Shrimp, Guppy, Neon Rainbowfish, Cardinal Tetra, Black Neon Tetra, Rummy Nose Tetra, Bloodfin Tetra, Congo Tetra, Glowlight Tetra, Serpae Tetra
DietCelestial pearl danios will eat live food, such as live baby brine shrimp, krill, daphnia, moina, white worms, and grindal worms.
LengthAround 1 inch once fully grown (at 3 months old).
Sexual DimorphismMales are thinner and have steel-blue to deep blue body coloration, while females are plumper with a light blue body coloration.
Breeding DifficultyCelestial Pearl Danios are easy to breed.

Water/Tank Recommendations

Water TypeFreshwater
Water TemperatureThe ideal water temperature for celestial pearl danios is 72-76°F (22-24°C).
Water pHThe ideal pH for celestial pearl danio is between 6.5 and 7.5.
Water HardnessThe ideal water hardness for celestial pearl danio is 5 to 12 dGH.
Tank sizeThe minimum tank size for Celestial Pearl Danios is 10 gallons, but the recommended tank size is 20+ gallons.


Celestial Pearl Danio (also commonly known as Galaxy Rasbora) are a gorgeous freshwater fish that we’ve been a fan of for years. If you’re looking for something simple but beautiful, this is the species for you!

Caring for these fish is relatively easy as well. This makes them perfect for those who are hoping to raise some fish without having to worry about complicated requirements.

This guide provides everything you need to know about Celestial Pearls Danios, from care and breeding tips to ideal tank mates and loads more.

About Celestial Pearl Danio

The Celestial Pearl Danio is yet another species from the growing list of nano fish. Like so many other small freshwater fish, this species is a popular choice for aquarists who are looking to create a smaller tank or have space constraints.

The Celestial Pearl Danio hails from Southeast Asia, specifically Myanmar, Thailand, Laos, and Cambodia. The common name “Galaxy Rasbora” comes from the fact these fish are covered with tiny white pearls all over their bodies. If you look closely, these pearls look a little like the night sky – hence “Galaxy.”

They also go by the name: Celestial Pearl Danios (or just plain “Danios”). These colorful freshwater fish are great for anyone looking to add excitement and color to their tank!


The Celestial Pearl Danio is aptly named after the celestial pearl spots that cover its body. The fish also has a red stripe that stretches horizontally from behind the gills to just above the caudal fin. The base of this stripe may blend in with the fins, but it’s still noticeable when they are flared or extended during playtime.

Their Length

The typical Celestial Pearl Danio size is around one inch long when mature. Most fish will be nearly this size at 3 months old.

However, there is a chance that they’ll get even larger. Some have been reported to grow up to 1.5 inches in length.

If you’re looking for a small fish with a big impact, the Celestial Pearl Danio might be just what you need!


The average Celestial Pearl Danio lifespan in an aquarium is about two years. However, it’s not uncommon for these fish to live longer (even past 3 years).

Fish that come from a reputable seller have the best chance of reaching this maximum lifespan. Of course, keeping them in a healthy environment that is close to their natural habitat ensures that these fish have a great chance of thriving and living as long as possible, too.

Sexual Dimorphism

Males and females are quite similar. The only difference between the two is that males tend to be thinner and have a steel-blue to deep-blue coloration, while females are plumper with lighter blue coloring.

You can also figure out the gender of your fish by looking at its anal fin. Males have an extended anal fin ray. Females don’t have this feature.


Celestial Pearl Danios are found in small streams and ponds throughout Myanmar, Thailand, Laos, and Cambodia.

These fish live among dense vegetation in shallow waters with sandy bottoms. They’re often found close to the shoreline or near weedy plant beds.

Because of their preference for warmer water and low-light conditions, they are considered an ideal species to breed in captivity.

Celestial Pearl Danios are bred in large numbers in fish farms around the world. They’re a favorite among aquarists looking to add some color and movement to their tanks!

Caring for Celestial Pearl Danio

Celestial pearl danios are a joy to take care of. They’re hardy fish that do well in most tank conditions and environments.

They don’t require any unique equipment or high-end filtration systems, which makes caring for them pretty straightforward. You only need to ensure your water quality is adequate and consistent (more on that later).

Below are some tips on how to best take care of these freshwater fish:

  • Always keep the water in your tank clean and clear. Spend some time keeping algae and debris off of the surface!
  • These fish prefer warm tropical temperatures.
  • Celestial pearl danios prefer slightly softer water than most other freshwater aquarium fish. Aim for a hardness level slightly below average.


Celestial pearl danios are carnivores that feed on live foods. They readily accept baby brine shrimp and bloodworms, which can be used as their primary diet in the aquarium. You can also provide them with cyclopeeze flakes or pellets to supplement their protein intake. Live food is usually preferred by celestial pearl danios.

How Often & How Much to Feed Them

Celestial pearl danios are not picky eaters. They’ll feed on most foods that you provide. One of the best ways to keep them healthy is by feeding them a varied diet daily.

Aim to feed them twice daily with as much food as they can finish in around 3 minutes. You may have given them too much food if they’re still eating after this point.

Possible Diseases

Celestial Pearl Danios are very hardy fish, but they can still suffer from common freshwater diseases like ich and fin rot.

Bacterial infections cause fin rot which then eats away at the fins of your fish. Ich causes white spots to appear on the skin. Both conditions are highly contagious among other fish species as well as Celestial Pearl Danios.

Fortunately, both diseases are avoidable with proper quarantine practices before adding new fish to an aquarium setup. Also, keeping water conditions close enough to natural bodies of water will help keep disease-causing microorganisms at bay.

Tank Setup

To get the most out of your Celestial Pearl Danios, make sure that their tank setup resembles their natural habitat the most. These fish come from freshwater lakes and streams with a lot of vegetation around them.

Start by filling the bottom of your aquarium with sand substrate material or fine gravel to replicate sandy environments in Myanmar. Then, add large rocks and driftwood for shelter (the fish will hide among these things when they feel threatened).

Decorating your fish tank with living plants is a great idea, like Anubias Barteri or Java Fern at one end; aquatic grasses such as hornwort work well, too. The plants are great because celestial pearl danios are used to hiding among these underwater greenery whenever they feel threatened by predators in their native environment! It also gives them places to reproduce naturally once you have a healthy breeding colony going.

Aquarium Size

For the first couple of months, a 10-gallon tank would be sufficient. As they grow bigger, you may need to upgrade the tank size, especially if you and add more fish to the mix.

If you can start with a 20+ gallon tank, this is always preferable. The more space for your beautiful fish, the better!

Water Conditions

Celestial pearl danios prefer warm waters that are neutral to ever-so-slightly acidic. These fish can adapt to cooler temperatures, but warmer water will help keep their colors bright.

These freshwater tropical fish come from slow-moving bodies of water in the wild. It’s more important to ensure there aren’t any sharp rocks or other items on the bottom of the tank where they might get injured.


The ideal pH for Celestial Pearl Danios is between 6.5 and 7.5. As long as you keep their water in that pH range, they will thrive!

You should consider obtaining a test kit and monitoring the water parameters every couple of weeks. You’ll be far more relaxed knowing that your fish are in the best habitat possible.


The ideal water temperature for celestial pearl danios is 72-76°F (22-24°C). Temperatures that are either too cold or hot can have adverse health effects on this species, but they quite hardy and will tolerate going a little outside of this range either side.

NOTE: Make sure to keep the tank away from windows and doors that could let in drafts. Drafts, especially cold ones, will cause temperatures to drop significantly in a short period of time.


The ideal water hardness for celestial pearl danios is 5 to 12 dGH.

Aim to be within this range, and this will provide your fish with the best chance at a long and healthy life.


Celestial pearl danios don’t need a particularly powerful filtration system. A hang-on-back filter or an internal filter will suffice. If your aquarium has many plants and hiding spots, consider getting a larger filter with more power.

Whatever you choose, ensure the filter can keep nitrate levels low. This will not only help the health of your fish, but it should also prevent algae from forming.

Aquarium Plants

Celestial pearl danios like to stay close to plants. They often use them for protection, as well as a source of food.

Live plants work perfectly for this fish species. Choose from sword, hornwort, or Java moss if you want tropical-looking plants in your tank. Avoid plants with large leaves or spiky edges that could harm the fish.

You could also try using silk plants or aquarium decorations. As long as the fish has some shelter and something to eat, they will be fine with artificial decor.

Behavior and Compatibility

Celestial pearl danios are schooling fish. They perform optimally in sizable groups. The more, the better!

These fish will swim around together and dart away from trouble as a group when necessary. It’s quite fun to watch them play with one another! When they aren’t doing that, you can expect to find them exploring every nook and cranny of your tank, looking for food or shelter.

Celestial Pearl Danios are very peaceful fish. They get along with most other species and usually mind their own business when left alone. When they’re in a group, these fish can even co-exist with larger aggressive tank mates.

How Many to Keep Together

The minimum number of Celestial Pearl Danios you can keep in a single tank is six. However, we recommend keeping as many as possible! These fish are highly social and need to live in large groups.

At least six fish will make them feel more secure and significantly reduce stress levels, leading to better health overall.

NOTE: You might notice that these freshwater fish start breeding when there’s a larger group living together (more on that later).


Despite their small size, Celestial Pearl Danios have a big personality. They’re active swimmers and will zip around the tank in groups to explore every nook and cranny of the aquarium.

These fish are very social and will spend a lot of time with one another. When kept alone or in a small group, they tend to be more shy than usual.

In large groups, however, these fish become much more confident as they swim freely through your tank.

Tank Mates

The best tank mates for a celestial pearl danio are other celestial pearl danios! They are schooling fish and do better when kept in groups.

Smaller groups may cause stress, as the fish will easily get scared. Larger schools are far better.

Here is a list of compatible tank mates for Celestial Pearl Danio:


Celestial Pearl Danios are one of the easier fish to breed in captivity. You can raise a large group together without worrying about aggressive behavior.

To start breeding, you’ll want to ensure that there are plants or hiding spots for the eggs in your tank. You should also raise the temperature by a couple of degrees to get things kicked off. The males and females should pair up before releasing their eggs into the water column!

You should consider removing the eggs to a separate tank to ensure that none of them get eaten!

Are Celestial Pearl Danio Fish a Good Choice For Your Tank?

Celestial pearl danios are a fantastic freshwater species that bring beauty and fun to the tank. They’re also quite low-maintenance, which is always a plus!

If you desire a fish that will bring some color to your aquarium without requiring tons of work, this should be right up your alley. These fish have proven themselves as excellent candidates in these areas time and time again.


  • Celestial Pearl Danios are hardy and easy to keep.
  • They’re also highly attractive fish that will add a splash of color to any tank setup.
  • Unlike other small freshwater species, celestial pearls do fine in slightly warmer water temperatures. This makes them more flexible than some other nano-species on the market.
  • Speaking of flexibility, these fish can be kept with several different types of aquarium inhabitants without an issue. This means you have plenty of options for community tank setups!


  • The major issue you’ll encounter with Celestial Pearl Danios is an overpopulation of fish. While these fish are easy to breed, they can easily become pests in a closed aquarium environment.
  • Overcrowding your tank with too many celestial pearl danios will lead to poor water quality and health issues for the fish.


Celestial Pearl Danios are a fantastic choice for freshwater aquariums of all sizes. They’re tough, gentle, and simple to look after.

To us, they don’t get any more low maintenance than that!

Please let us know if you have questions or suggestions about this species or ideas on how we can improve this guide!

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