Celestial Pearl Danio: Care Guide, Breeding, and Tank Size

Celestial Pearl Danio: A Brief Introduction

Celestial Pearl Danio, also known as Galaxy Rasbora or Microrasbora Galaxy, is a small, colorful fish native to Thailand. It is a popular species in the aquarium trade due to its vibrant patterns and peaceful nature.

Celestial Pearl Danio: Overview

Imagine a colorful freshwater fish that, at this point in time, has only been found to live in Inle Lake, in Myanmar, South East Asia, and a fish that was discovered as late as 2006! Sound interesting? It is! We are talking about the celestial pearl danio – the danio margaritatus or celestichthys margaritatus, which is also known as a galaxy rasbora.

Freshwater Aquarium Fish

Its bright colors and small size landed it almost instantly in aquariums all across the globe, and when you see the way its body bounces off light, it is not hard to understand why someone would want one of these beauties swimming around in their living room fish tank. It may be a new species, but its popularity has been steadily climbing, and if you are not familiar with the danio margaritatus already – you will want to keep on reading.

Information ChartCelestial Pearl Danio
Scientific Name: Danio Margaritatus
Family: Danionidae
Care Level: Easy
Temperament: Peaceful (aggressive males)
Color: Red, Blue
Lifespan: 3-5 yrs
Size: 0.75-1 inch
Diet: Omnivore
Minimum Tank Size: 10-20 gallons
Temperature: 73 to 79˚F
Water: 2 – 10 dKH
Tank Mate Compatibility: Other Peaceful Similar Fish

Celestial Pearl Danio: Appearance

The Celestial Pearl Danio is a species of bony fish, and it comes in the family Danionidae. These species associate themselves with freshwater habitats. The individuals can attain a growth of up to 2.1 cm. When it comes to the physical description of this fish species, the males are deep midnight blue. They possess a series of spots on them. Those spots are pearlescent and appear over their flanks. We can also find them arranged in rows.

In addition to that, they showcase unpaired fins. We can find bright red stripes with a midnight blue outline on those fins. They also have ventral fins that appear solid red. These ventral fins are also filled with red spots.

A group of fish swimming

Description automatically generated with medium confidence

We can also see peculiar features in the males. They show a red belly that is bright in appearance, and we can find a red stripe on their backs as well. The stripe is visible from the top of the head to the dorsal fin. We can often see the photos of the male Celestial Danios with the distinct bright red colorations on their backs. The male Danios can be witnessed adopting a head-down posture. While doing so, we can see their flash at its best appearance.

The female Danios usually appear a bit more washed out. They normally possess an overall golden blue sheen. Unlike the males, we cannot find the bright pearlescent spots on them.

Moreover, the red color of their fins takes the appearance of a faint orange tinge. In females, we can find clear ventral fins. However, while some may develop an orange color in the belly, most of them retain their original golden color.

The females also develop a dark spot that can be visible in the front of their anal fin. It usually occurs when they are prepared for the spawning process. As a result, the area also swells up slightly. The swelling may result from the egg tube’s extension or maybe because of the swelling near the urogenital pore. 

Therefore, we can say that it was the appearance of the celestial pearl danios that first caught the attention of fish tank enthusiasts, and it does indeed have a very distinct look. The fins tend to have a red or orange-colored tone, which is more intense than others, and two black stripes run parallel down each fin. 

Male galaxy rasbora fish tend to have fins that are brighter and more intensely red than those of female fish, which means you can often determine the sex of the fish by simply looking at it. The color of the male celestial pearl danio fish is also bluer in tone compared to the greener tone of the female.

As a result of the transparent gill covers, you can also see the red gills.

When you see this species in pictures, it is easy to believe that it is bigger than its actual size, and many are surprised by its small size once they see them swim around in the water. The body usually isn’t any larger than 1 inch, and it is a small fish with the ability to make a big impression.

Lifespan Of Celestial Pearl Danio

A Celestial Pearl Danio’s typical lifespan is between 3 and 5 years. We must avoid certain conditions while keeping them in captivity as they can impact their lifespan. The two main ones are water conditions and stress. So, if provided with the most suitable water conditions while the Danios are in captivity, they can even live up to 5 years or more. 

However, one more thing needs to be kept under consideration. Since this fish is a species of nano fish that are very small in size and, on top of that, are peaceful, you must not pair them with aggressive fish. Along with the water quality, such a situation could also reduce their lifespan.

Celestial Pearl Danio: Size

The typical Celestial Pearl Danio grows up to 0.75 inches on the lower end and up to 1 inch or 2-2.5 cm in length for larger specimens when they attain full growth.

Most Danios will reach that size when they are about 3 months. So, when they attain their sexual maturity, we can find these nano fishes up to an inch long. Such small-sized fish can be a great addition to the nano tanks as they occupy less space yet enhance the beauty manifold. 

Natural Habitat and Origin

What is so fascinating about the celestial pearl danio is that it has only been found in one small part of a lake – not known to exist anywhere else. That does not necessarily mean that it does not swim in waters elsewhere, but its natural habitat – as believed today – seems to be only in a small specific part of a lake in South East Asia. There is almost something mythical about a fish like the celestial pearl danio (galaxy rasboras), and who wouldn’t want that in their tank?

We can find the Celestial Pearl Danios or the Danio Margaritatus in a series of spring-fed ponds or groundwater when it comes to the habitat. These species are found in water bodies, especially in the Shan plateau, where the Salween river passes.

However, the Danios typically occur in several ponds as per various reports. Those ponds are typical to the mountainous region in Hoping town, located on the outskirts of the Shan state capitol. The region is located at an elevation of more than a mile. The area primarily consists of rice paddies and grasslands as the main agricultural commodity is rice there. Because of the same reason, the ponds receive plenty of sunlight and are rich in various aquatic plants. 

Celestial pearl danios were first discovered in 2006. While they originally belonged to the genus micro rasbora, a study performed two years later – in 2008 – uncovered that the galaxy rasbora wasn’t a micro rasbora, but instead belonged to the danio genus. With this in mind, the celestial pearl danio is a fish species full of surprises, and there are probably many more things left to discover when it comes to this shimmering freshwater fish.

An intriguing anecdote regarding celestial pearl danios is how a rumor started going around the fish becoming incredibly rare when it wasn’t the case. That started approximately six months after the species was originally discovered. People in the aquarium industry and the keepers believed that a celestial pearl danio was not the easiest to get ahold of. It is believed that this resulted from the veterans struggling to breed the fish (more on this below). Still, the wild celestial pearl danios were never under threat, nor were the population ever significantly reduced.

The evolution of the Celestial Pearl Danio allowed it to take maximum advantage of such natural features. If we keep in mind the natural habitat of the danio, it will allow us to set up a tank that resembles the native place of the fish.

Various reports suggest that most water has either low carbonate or is neutral with low conductivity properties. As a result, hobbyists worldwide experience successful spawning in different waters. It can range from soft acid water to hard water.

Therefore, regardless of the location, be it Central Europe or Southeast Asia, the exact parameters may have a low impact as far as the water is clean. That means if the water is periodically changed and the nitrates and dissolved chemicals are kept low, it may be possible for the Danios to sustain themselves without exact requirements.   

The natural habitat of the Danios is situated at high altitudes where the water temperatures are not tropical. The temperatures can reach a near-freezing temperature during the winters, and they can go as high as 95°F during summers.

However, there have been reports of successful keeping of the Danios in low temperatures, even reaching down to the 70s. However, it would be wise to avoid keeping the Danios in heated tanks and follow the temperatures that resemble its habitat.

Celestial Pearl Danio: Care & Tank Set-Up

The tank setup of the Danios should effectively replicate their home environment. Therefore, including plenty of small plants with a dark substrate is necessary. The natural habitat for these fish consists of mostly ponds that accustom aquatic plants. So, including them will help in imitating the same habitat. Moreover, the aquatic plants will clean the tanks and create a comfortable environment to lay eggs.

It isn’t just the tank mates you need to worry about or how many male fish you have in one tank; you also need to see the bigger picture and ensure the aquarium is adapted and apt for this specific species. The temperature should be kept somewhere around 73-79°F to mimic the natural conditions of where a celestial pearl danio lives, and one more thing to keep in mind is that the water should be soft or medium with a PH of 6.5 ranging between 7.5 PH. These are fairly common aquarium water conditions, and the way to interpret it is that one of these bright red danio fish isn’t too hard to care for in terms of tank conditions.

Danios do like to hide, so the aquarium should have plenty of plants (preferably plants that are dense and good to hide in) that are good for the water conditions required, and this is especially important if you have multiple male fish. A good rule of thumb, other than plants, is to have at least 10 gallons of water. 

Still also, if you have many of these small and peaceful fish in your aquarium (whether male or female), you will need to adjust this accordingly and possibly use a larger fish tank with more water. If you get several plants, what the fish is expected to eat, and the water quantity is right, you will see how easily it adapts to its new living conditions inside the fish tank.

Celestial Pearl Danio: Tank Size and Specifications

Since the Danios are a small fish species, the tank requirements are relatively smaller. However, maintaining the optimum requirements is necessary to keep them safe and comfortable during their captivity.

Optimum Tank Size For Celestial Pearl Danio

The recommended tank size for Celestial Pearl Danio is 10 to 20 gallons. You can easily keep 5-6 individual fish without any hassle. However, adding 2 gallons to the tank is recommended for every new fish.

Tank Shape For Celestial Pearl Danio

Since the fish are small and you may add in 5-6 individuals together, choosing a cubical tank that allows more length for their free movement is recommended.

Filter Type

The Celestial Pearl Danios need a strong filter that fulfills their tank filtration requirements. Their natural habitat provides them with clear water. Therefore, we must ensure that the tank water has low nitrates and carbonates and is free from contaminants. The physiology of these fish may not allow them to deal with many pollutants. So, a strong filter must be installed while keeping them in captivity. 

An ideal choice could be a canister filter or a power filter. However, you must be careful in blocking the inlet tubes after their installation. That will prevent these small fish from getting sucked into them. Also, since these are quieter fish and prefer free movement around the tank, you must adjust the power filter to provide a moderate flow.


The Celestial Pearl Danios like swimming around the middle of the tank. However, they also tend to dwell near the bottom of the tank. But, they don’t have the habit of digging into the bottom. Therefore even a soft substrate would not get scattered because of them. So, you can choose a substrate that blends well with the plants kept inside the tank. Dark fine sand can be a great choice as the ideal substrate. It will act as a soft substrate that won’t harm the fish and allow the plants to flourish well. A dark fine sandy substrate is also clean, which adds another benefit by contributing to the tank’s hygiene.

How Many Celestial Pearl Danio Should be kept In a 10-20 Gallon Tank?

You can safely add 5-6 individual Danios in a 10-20 gallon tank. However, with each new fish you add, the capacity must be increased by 2 gallons. It allows them to move and swim around freely without harming each other.

Water Parameters For Celestial Pearl Danio

Water Temperature

The ideal water temperature for Celestial Pearl Danio is 73°F to 79°F. So, if you maintain the same temperature range, it will allow the fish to thrive and survive without any trouble.

Water Flow Rate

The Galaxy diaspora or the Celestial Pearl Danio requires a moderate flow rate. That will allow them to swim without hindrance in the tank.

pH Level

The perfect water pH level for Celestial Pearl Danio is between 6.5 and 7.5. Such a pH range is ideal for them to survive as it will mimic their home environment. 

Water Hardness

The water hardness level should range between 2 – 10 dKH. Such a range will provide a medium hardness, ideal for the fish’s survival.

Celestial Pearl Danio Tank Landscape

It would be best to plant your 10-20 gallon tank with heavy vegetation. The landscape should include a dark substrate to allow the plants to thrive easily and make the Danios feel safe.

Best Plants For Celestial Pearl Danio Tanks

  • Java Moss
  • Java fern
  • Rosettes

As long as the plants provide the necessary shade and cover, the variety of plants does not matter. You can add bushy plants to the tank, as that would be a great addition and help during the spawning process.

Worst Plants For Celestial Pearl Danio Tanks

  • Water hyacinth
  • Ophiopogon Jubaran

Decorations For Celestial Pearl Danio Tanks

To improve the landscape, you must also add rocks and driftwood to mimic their natural environment.

The Danios prefer weedy and slow-moving streams in the wild, so the tank setup also requires essential hiding places. You must also remember that they prefer calm and shallow water in their natural habitat. Therefore, you must set up the tank accordingly.

Lighting For Celestial Pearl Danio Tanks

If you keep bright lighting in your planted tank, it will benefit the fish.

Moreover, the more plants and places to hide the tank, they will feel more secure. It will help them while laying eggs.

Nitrogen Requirement For Celestial Pearl Danio Tank

You must monitor celestial danio’s tank for its nitrogen cycle. It is crucial to maintain its health.

Leaving the water untreated or uncycled can cause an accumulation of toxins consisting of ammonia, nitrite, and nitrates. The fish waste will produce ammonia after a pH of 7. 

Once the ammonia starts accumulating,  a bacteria starts to eat it formin cloudy water. The further ammonia decline will increase nitrite as the Nitrosomonas start to oxidize the ammonia. After that, Nitrobacter will develop and converts it to nitrates. You must watch for it not to exceed 20ppm. If it exceeds that, perform regular partial water changes of 20-50% every 1-4 weeks.

Maintenance And Care

In general, these small and colorful fish are quite easy to keep, and it is a species that does not require much to thrive. However, despite being the same species, the fish will have personalities, and some may be more forward than others. When it is time for food, that can be an issue – a small issue but still something worth knowing. 

If some of your fish are sheer, there is always a risk that they won’t reach the food in time and will not get the required nutrition for these small aquarium inhabitants. The easiest way to solve this without wasting too much time is by feeding the quicker danios on one side of the tank and the slower ones simultaneously, but on the other side, ensuring that everyone gets their daily meal.

The celestial pearl danio may be small, but they are set in their ways! Many are not fond of being fed the same food every day, so try to feed your small fishies a varied diet where you change it up from time to time to prevent boredom and lack of interest in your fish. That is true for many types of fish, but a danio appears to thrive in an environment where they get variety in terms of food.

Feeding Celestial Pearl Danio

Feeding the danios may not be a hefty task as they are mainly omnivores and are not picky eaters. They feed off algae and plants in their home habitat and planktons as their favorite snack. Some small vertebrae may also serve as a source of protein for them.

Since they mostly like to dwell near the bottom of the tank, you must ensure that the food reaches them properly.

You shouldn’t overfeed the fish. That may pollute the tank and make it dirty.

It would also be best to remember that these fish have small mouths, so investing in pellets and feeding them in small quantities would be ideal.

Best Diet For Celestial Pearl Danio

Their natural habitat lets them munch on numerous algal species, plants, and zooplankton. They also consume small invertebrates and worms as their protein source. 

So adding such meaty foods to their diet may be the best way to satisfy their hunger. You can also add pellets and flakes to supplement their diet. But, you must ensure that those fit into their mouth as they are small. 

You can add frozen food such as brine shrimp or krill to their diet, which would help maintain their red coloration. At the same time, white worms can be a low-cost alternative. The best diet would not contain only pellets, but a cycle of other nutritious food sources such as Live Daphnia, Grindal Worms, Moina, etc., will help enrich it.

How Often Should You Feed Celestial Pearl Danio?

Celestial Pearl Danio should typically be fed every 3-4hours/ day. That means you can feed them approximately 3-4 times in different slots each day. That would prevent overfeeding and will allow you to cycle their diet effectively.

Celestial Pearl Danio: Behaviour And Temperament

The danio is a small fish that goes about life in a relaxed, calm, and peaceful way, and it can be a true joy to have them swimming around among the aquatic plants.

As long as they have food to eat, a place to hide, and a few friends, the celestial pearl danio tends to thrive in those environments.

The key is to consider the natural conditions in the small area, say, where in the wild they’re found, and try to replicate this in the tank. These are great tank fish for someone who wants a species that looks stunning (those fins are one of a kind), but fish that does not require much and is laid back and pacific.

Celestial Pearl Danio Tank Mates

The celestial pearl danio does well with other fish of the same species, so make sure you have around five or six, provided the size of the fish tank allows it. You can keep male fish together, but you should be wary of having too many unless you have enough space in the fish tank with plenty of hiding places. The male pearl danio can get a little territorial if this does not become an issue and if the tank has enough hiding places.

Due to its peaceful nature and small size, it can easily fall prey to more aggressive fish, such as Oscars, cichlids, or Jack Dempseys, and it is a bad idea to have these together in a tank. It is unfair to this beautiful, bright, red-fined species, so they choose their tank mates wisely. 

A species like this one will blast swimming through the aquarium water with the right tank mates, and their red fins tend to look a little extra. Their calm personalities make them good fish also for a beginner.

To be aware of is that the celestial pearl danio may threaten your young brine shrimp if you keep brine shrimp in your fish tank, as they are known for killing and eating them. However, this only applies to the young shrimp, and by the time they are adult brine shrimp, they are usually perfectly fine and can live in harmony and the same water with the danio.

Bad Tank Mates For Celestial Pearl Danio

  • Oscars
  • Cichlids
  • Jack Dempseys

Breeding Celestial Pearl Danio

As mentioned previously in this article, the breeding process is a little tricky in the beginning, but this seems to have changed, and it is now very straightforward and uncomplicated. It distinguishes the male from the female based on the fins and body color, and one thing that is also helpful is how the female begins to change the body shape and color of the fins as she becomes ready for spawning. Look for a deeper red color of the fins and a belly (the fish abdomen) that appears rounded, and that way, you will be able to see that she is ready.

Changes in body shape are not the only step of this species’ breeding process, and another thing that might also be relevant is what food your danio eats. These fish are more likely to spawn if they are fed live food, possibly due to what they would eat in the wild, so if you are unsuccessful – consider changing the food they eat, at least temporarily. It is always good to see if you can get some advice from your local pet store, provided there is someone with experience. The female Danios are egg layers, and you can distinguish them because once they are ready to spawn, they become darker in color. They also have a more rounded abdomen.

Once they are ready, the females can spawn almost regularly. The females can lay them anywhere, but they usually prefer still water. The eggs have an incubation period of 2-4 days, after which they reach their larval stage and start swimming.

Fish like this species can lay up to 30 eggs in one go, but they may also lay significantly less or take a break between each cluster. You might not always be able to see the eggs, but if you do, you must take action to move them over to a separate breeding tank for your newborn danio fish to hatch and grow eventually. Setting up the breeding tank is not too difficult, as the conditions in the fish tank should be very similar to what they are in your main fish tank in regards to PH, water hardness, vegetation, food to eat, and size.

Celestial Pearl Danio Breeding Level


Celestial Pearl Danio: Sexual Dimorphism

To distinguish between male and female Celestial Pearl Danio, we must look at their color and size. The males usually appear thin and showcase a vibrant color. It is visible, particularly on their tails.

On the other hand, the females appear dull in color and have a round shape.

Celestial Pearl Danio: Common Diseases And Their Treatment

Fin Rot

Since the Celestial Pearl Danio is a freshwater fish, it is vulnerable to all freshwater diseases.

However, Fin rot is a disease that is particularly noticeable with the Danios. You can identify fin rot with certain visual symptoms. If you notice visual markers on their fin’s edges or if they look frail or discolored, that may indicate the disease. Also, if you notice any disintegration, you can confirm that danio has contracted this disease. It is a bacterial infection that is caused by the bacterium Pseudomonas Fluorescent.

Other than that, various other factors can also contribute to Fin rot. Most commonly, poor water quality can result in that disease. However, if the reason is the water condition, you can easily avoid that by monitoring the pH levels and adjusting them accordingly. A good water testing kit can come in handy for that purpose.

The male danios spend most of their time courting females, making them fight with each other very often. So fighting can also cause fin rot. But, you can prevent it by ensuring a low male-to-female ratio in the tank.

Fewer males mean lower aggression and competition, which would prevent any harmful fighting.

However, if the fin rot is caused due to bacterial infection, you can use an antibacterial medication as a treatment. If used correctly, it would eventually allow the fins to grow back.

Facts About Celestial Pearl Danio

  • Celestial pearl danios are tropical fish that is usually peaceful.
  • They are usually small species reaching only up to 2.1 cm in length and weighing just 0.2 lbs
  • When the spawning time arrives, the females become darker in color.
  • They noticeably look slimmer after the spawning with the males. 
  • They can lay up to 30 eggs in one go.

Are Celestial Pearl Danios Right For You?

Celestial pearl danios are an amazing addition to your aquarium. But, their beauty can blend into your aquarium only if you have a highly vegetated tank. It should be above 10 gallons, and you must be ready to watch for its diet and breeding requirements.

If your tank is small or there is not enough vegetation, you should consider Guppies instead.


A perfectly balanced fish tank is a wonderful landscape for any keeper. Danios are excellent additions for anyone who wants a little bit of additional color added to the mix. A few things are important to know before bringing one of these fish into a tank. 

Most have already been covered in this article to help you make an educated decision based on solid facts. You will find a few common questions asked about the celestial pearl danio.

Are Celestial Pearl Danios Hardy?

These avid little swimmers are hardy fish, and they are resistant to temperature changes and different PH values. One thing that has aided in their rising popularity as they are quite easy to keep alive in hardy water. 

Does Celestial Pearl Danios School?

Keeping a danio school is doable, ensuring you keep the tank properly equipped and conditioned. It is recommended to read up on the subject if you think you will be interested in it and always condition the tank with the danio and its needs in mind.

What Do Celestial Pearl Danios Eat?

Known as opportunistic feeders, these fish tend to eat a bit of everything, depending on their encounters. They eat different plants, zooplankton, and algae but may also eat brine shrimp and other similar things. Be aware that a danio isn’t too fond of the same food, so it is good to change it up a little by feeding different things.

How Big Do Celestial Pearl Danios Get?

A danio does not usually get bigger than approximately 1 inch, and they are perfectly small and slim fish for almost any type of fish tank. Their reduced size does not mean you should keep them in a small tank, as all fish need space to swim around.

celestial pearl danio


Having the small celestial pearl danio fish in your tanks is a great idea as long as you have the right setup and suitable tank-mates, and it can add a nice touch of color and variety to your aquarium. Keep in mind that this is still a very new species, considering it was discovered as recently as 2006, so there are still many things we don’t know about it, and our knowledge of the fish will likely expand in the upcoming years. There will likely be additional discoveries made in the future, which should be something to look forward to!

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