Celestial Pearl Danio – aka Galaxy Rasbora or Microrasbora Galaxy

Celestial Pearl Danio
Celestial Pearl Danio is a recently discovered, a small cyprinid fish from Burma (Myanmar). It is a tiny freshwater fish from ponds, part of the Salween region, Myanmar.
This 1 inch (2.5 cms) size jewel has an instantly captured the attention of hobbyists. There is no doubt this celestial beauty, a skittish swimmer, will be a great addition to your community tank.

Celestial Pearl Danio – An Overview:

Description Category
Family Cyprinidae
Scientific name Danio Margaritatus
Origin Burma aka Myanmar
Type Fresh Water
Color Form Deep Blue Body Covered with White Pearl Spots
Difficulty Moderate
Breeding Easy
Max. Size 1 inch (2.5cms)
Life span 3 to 5 years
Temperament Peaceful
Diet Omnivores
Minimum Tank Size 10 gallon ( liters)
Temperature 72 – 80°F (22 – 27°C)
Acidity 6.5 to 7.5 pH
Hardness Soft to Medium

Species Origin, The Celestial Pearl Danio:

The Celestial Pearl Danio, scientific name Danio Margaritatus is also commonly known as galaxy rasbora, Microrasbora sp. galaxy, Fireworks rasbora. It was discovered in 2006 by some aquarists in Nam Lang and Nam Pawn rivers, the Salween basin.

The fish was initially known as galaxy rasbora. On February 28, 2007, Tyson R. Roberts of the Smithsonian Tropical Research publication derives a conclusion that this newly discovered tiny freshwater fish from Myanmar is danionins, related closely to Danios rather than Rasboras.

Roberts conceived the generic name for the fish as Celestichthys, in Latin and Greek means heavenly fish. Margaritatus, meaning adorned with pearls. Celestichthys Margaritatus means Heavenly fish adorned with pearls. Hence, it gets the name Celestial Pearl Danios.

Celestial Pearl Danios became an immediate hit among the aquarists right after its discovery due to the Internet. They became very popular as they add natural color to the tank. 

To date, it has been seen only in a small area near Hopong, east of Inle Lake, at an altitude of about 3300 – 5000 ft (1000 – 1500meters). The fish lives in shallow water bodies created around grassland and paddy fields.

Up until the discovery of Celestichthys Margaritatus by the aquarist in 2006, it was a kind of protein source for the local population.

Galaxy Rasbora – Physical appearance and Characteristic:

Male and female physical appearance

Doubtlessly, the reason for the celestial pearl danio’s popularity among the hobbyists goes to its distinct look.

Celestial Pearl Danios are small fish at most they reach 1 inch in length. They reach their fullest growth from anywhere between 6 months to 1 year.

The Galaxy Rasbora shows sexual dimorphism. 

The female of the species has a blue-green body-color with golden-cream colored pearly spots. 

While the male of species has a deep blue body coloration, which extends to the side of the body with cream-colored pearly white spots. 

They have an orange-reddish color abdomen and a pale stripe running over the top of the head makes them distinct. While the female has a greenish-blue body and a yellowish-white abdomen. The red gill shines through the transparent gill covers.

They have orange-red colored fins. Males fins are brightly colored than the females of the species.

They have tall bright dorsal fins stands erect. They have 2 pelvic fins and unpaired tail fins. All the fins have a pair of parallel black lines. In females, this pattern is a little duller. 

The females grow larger and rounder than the males.

At the sexual maturity, the females develop a black spot between the belly and the anal fins, while the males develop a red belly, including both sides of the body, which makes the back appear paler and makes them even more remarkable.

The males have a black dressing, contouring the lower jaw, which is absent or un-distinct in the females of the species. Their eyes look larger, in comparison to the proportion of their bodies. 

The juveniles have striped patterns over their dark blue/greenish-blue body, which transforms into a pearly pattern as they mature.

The Celestial Pearl Danio Lifespan:

The Celestial Pearl Danio lifespans anywhere between 3 to 5 years depending on the conditions of water quality and the living environment.

The minor change in the water quality and tank mates will have a great impact on their lifespan.

Danio Margaritatus Habitat:

Celestial Pearl Danio Habitat

Danio Margaritatus, the Celestial Pearl Danio is a freshwater nano fish from shallow ponds of the Salween Region, Myanmar. These ponds in the regions at an elevation of about 3300 – 5000 ft (1000 – 1500meters).

These ponds are spring-fed in the mountainous region of Hopong amongst the paddy field and grassland. The shallow water is exposed to the Sun and covered with a diverse variety of aquatic plants.

The pH of the water is around neutral or slightly alkaline 6.5 to 8 pH and low carbonate water.

Although these celestial beauties are from the tropical region, due to the high altitude, the water temperature in the shallow ponds varies from winter to summer.

Therefore, you might keep them in an aquarium tank without a heater, just the same as White Cloud Mountain minnow.

Tank Size and Conditions for Celestial Pearl Danio:

Tank Size:

The minimum required tank size for Celestial Pearl Danio is 10 gallons (38 liters). As they thrive better in a fairly big group, we recommend you to keep a minimum of 5 fish. This tank is ideal for a maximum of 6 fishes. If you are planning to have more than 6 fishes, consider setting up a bigger tank. Despite their nano size, they need plenty of space to swim.

Moreover, you need more space to plant and other decors to recreate their natural habitat. As a thumb rule, you should aim for 2 gallons per Celestial Pearl Danio to provide the optimal space for them to thrive.

Tank Conditions:

Celestial Pearl Danio originates from Mountainous region around Hopong, Myanmar. They live in ponds that are created by overflow springs and streams. 

These ponds are shallow and no more than 1-foot depth (30 cms). Their natural habitat is with dense vegetation similar to Canadian waterweeds and frogbits, etc.

Spring fed shallow water body covered with dense vegetation, open to the Sun has a wide temperature range from 68 to 80°F (20 to 27°C), with soft to medium water hardness and a neutral pH to slightly alkaline. They thrive better in a temperature range 73 – 79°F (22 to 26°C), pH 6.5 to 7.5, with soft to medium water hardness, and slow-flowing water.

Filtration and other equipment:

A sponge filter or a Hang-on-back filter is a good choice for small fish like Galaxy Rasbora. A sponge filter is a good choice for nano fish, as they provide sufficient filtration and gentle with the water-flow. 

A hang-on-back filter is also a good choice, as long as you take care to keep the inlet and outlet covered with a mesh to ensure the little pearls are not sucked into the filter.

These fish live in a water body that is completely open to the sun they are accustomed to plenty of lighting. You can use programmable LED lights. While setting up lightings for the tank, do not overlook the need for aqua-plants.

Substrate for Galaxy Rasbora:

Despite Danio Margaritatus, do not require any specific type of substrate, to replicate their natural habitat is to have a dark substrate. You can choose from sand, gravel, plant, etc.

Though they live bottom half of the tank, they are not diggers. Both sand and gravel substrates come in a variety of colors. You can choose to go with darker shades to clone their natural habitat.

Plant substrate comes generally in black or brown or red. They are more expensive compare to sand or gravel substrate.

Although my choice for the Celestial Pearl Danios is a dark sand substrate, you choose the substrate in line with the plants and the tank mates requirement.


Tank decors for Celestial Pearl Danio

As we already know they are from a densely vegetative habitat. Live plants provide multiple benefits in any aquarium tank. Celestial Pearl Danios are shy and need plenty of hiding places. 

The aqua plants and driftwoods along with some rocks can provide good hideouts and make them feel safe and secure.

Plants like Java fernRotala Rotundifolia, java moss, frogbit, etc make an excellent addition to the aquarium tank where Galaxy Rasbora lives. These plants help to keep the water conditions such as pH, dissolved oxygen, water hardness, and even temperature to some extent. 

Moreover, they provide plenty of covers for micro rasboras along with nutrients supplements.

Furthermore, these plants are an ideal place for eggs to secure themselves and for fry to hide from predators that include their parents.

Food and Diet:

Celestial Pearl Danios are omnivores and their diet ranges. In their natural habitat, they eat algae, plants, planktons, and zooplanktons

In the aquarium settings, you can feed them high-quality commercial fish flakes and pellets that sink as Pearl Danios stick to the bottom half of the tank. 

You can also feed them live/frozen brine shrimp, Daphnia, Grindal worms, etc. Just make sure to feed them a variety of food to give them a balanced diet. With the right diet, they will be active and vibrant. 

Do not over-feed them, observe while feeding how much they eat and how long do they take to finish eating. Avoid overfeeding in order not to pollute the water and encourage algae bloom. Algae bloom will lead to a reduction in the dissolved oxygen level in the fish tank, which can lead to the drowning of fish.

Behavior and Temperament of Celestial Pearl Danio:

Celestial Pearl Danios are shy and yet peaceful by nature. They constantly swim and explore the bottom half of the tank. 

They are not schooling by nature. Nevertheless, some aquarists disagree with it. Danio Margaritatus is a relatively new species in the aquarium hobby. So, we cannot rule out any reported behavioral pattern by the hobbyist.

However, the best practice is to keep a minimum of 6 fish if not more in any given tank. Many aquarists witnessed them swimming and exploring their habitat altogether. But, at the same time, they go around exploring independently as well.

There is another observation made by some other hobbyists is that females are peaceful and keep together. Sometimes, they even swim along with other peaceful tank mates. Whereas males are aggressive and the dominant male chase and attack other males, often results in killing the other male members. 

These aggressive behavior include chasing, circling with fins splayed while approaching other fish or vice versa, nipping, and bitings.

Experienced aquarists suggest keeping 1 male in a tank, adding more hiding spots with plants and other decors, rearranging the decors to shake up the territorial boundaries, etc. to keep the bullying situations under control. 

Often, isolating the bullies or having a bigger tank helps the situation as well. 

Tank Mates for Galaxy Rasbora aka Celestial Pearl Danio:

Danio Margaritatus-tank mates and habitat

Celestial Danio Pearl is a shy and peaceful freshwater fish. They can live around other species of the same size and nature such as tetras, guppies, chili rasboras, small corydoras, catfish, killifish, etc.

They also do well with those species which dwell in the middle and top half of the tank, such as ember tetra, neon tetra, etc. will make a good companion to galaxy rasbora.

You can also have them with shrimps such as red cherry shrimp, Amano shrimp, etc. Avoid keeping juvenile shrimps as Celestial Pearl Danios will eat them for a great snack. In the wild, zooplanktons comprise one of their main diets.

Fishes to avoid are the large and aggressive nature fish such as Cichlids, Oscar, Jack Dempsey, etc.

Celestial Pearl Danios make an excellent community fish with dozens of types of peaceful nature fish. 

Species only tank – Celestial Pearl Danio:

Keeping them in a species-only tank, that is densely packed with vegetation can add color and zeal to your tank. With the white spots filled against the dark-colored body and orange-red fins, Galaxy Rasbora will make your aquarium tank with dense vegetation astounding.

Keep a minimum of 6 Celestial Pearls of which only one male in a 10-gallon tank. If you wish to have more males double the tank size to demarcate their territories.

Danio Margaritatus – Care and Diseases:

Watching Celestial Pearl Danio closely from the beginning is very important as this is a relatively new species in the aquarium hobby. 

If you have more than one male Danio Margaritatus, watch for tell-tale signs such as circling, circling with fins beveled, nipping, mouth biting, torn fins, bite marks, color intensifying, etc.

If you see any of these you could isolate the aggressive one or rearrange the tank decorations like plants, driftwoods, caves, etc. to shake up the territorial boundaries, add more hiding places or simply move them to a bigger tank.



Skin rot is a common disease faced by aquarists due to poor quality of water circulation, wounded fins from fighting or scratching on the sharp edges of decors, etc. 

You can minimize or completely avoid by maintaining the recommended water parameters, running the filters constantly, and cleaning the tank periodically. Avoid decors with sharp edges.

You can treat the disease with anti-bacterial medications such as Oxytetracycline, Tetracycline, Chloramphenicol, etc. antibiotics that contain Malachite Blue best suit any member of the Cyprinidae family.

Increase the water change if you notice any fish having skin rot along with the medications.

Breeding Celestial Pearl Danio:

If you are interested in breeding Celestial Pearl Danio, first find out whether they were caught in the wild or bred in captivity. The one which is bred in captivity are more tolerant and adapted to the aquarium water conditions and the environment. 

Their behavioral adaptation to the captive environment will make it easier to breed them. However, they might produce weaker offspring.

You can purchase fish that are sold specifically for breeding purposes. 

Males have intense coloration especially during courting and spend most of the time around the females that are ready for spawning. 

Danio Margaritatus appears to have adapted ephemeral habitats. They don’t have a spawning season. As of now, they are still trying to figure out the spawning cycles. Some aquarists claim that they spawn almost daily, whereas the others claim they don’t continuously lay eggs either. 

They are egg-laying species, lay anywhere between 12 to 30 per spawning cycle. At 75–77 °F(24–25 °C), the eggs will hatch somewhere between 3 to 4 days. At first, the eggs are dark and mysterious and after about 3 or 4 days of hatching, they hide in the substrate or the plant.

After about 8 to 10 weeks of hatching, they transform into adults. The pearly spots and the fins’ color start to appear when they are about 12 weeks.

You need to set up a separate breeding tank that is densely planted as the males and the other fishes will constantly eat the eggs. Plants such as java moss or Rotala Rotundifolia supplies food to the fry as moss is the perfect place for infusorians to anchor and multiply.

You can feed them with dead brine shrimps. As they mature, continue to give them frozen food and also cautiously add micro pellets.

Keep the filtration gentle and slow. Need to keep the filtration inlet and outlet with a sponge bush.

Final Thoughts – Celestial Pearl Danio:

Danio Margaritatus aka Celestial Pearl Danio is a rather undemanding fish as long as its basic need for existence is taken care of. They are a hardy and beautiful addition to your peaceful community aquarium tank.

It is an excellent beginner’s species and is well suited for the tanks that are heavily planted with their relatives rasboras other colorful species such as tetras, mollies, guppies, etc.

Share with us, if you have had any experience with these pearls here below.

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