Celestial Pearl Danio: Size, Breeding, Care and More…

Danios are among the friendliest of aquarium fish.

There are many that you can choose from but the Celestial Pearl Danio certainly stands out as one of the best.

This tiny fish is well known because of their iridescent blue scales and bright orange fins.

They are one of the most beautiful fish in the aquarium hobby and are a favorite of aquascapers. Because they are compatible with just about any aquarium plant you can create an entire underwater garden for them to live in.

There is a lot to learn before you add a group of Celestial Pearl Danios to your aquarium.

This complete guide has all of the best information on care, feeding, habitat set up and so much more…

Celestial Pearl Danio

Celestial Pearl Danio
Other Common Names: Galaxy Rasbora
Scientific Name: Danio margaritatus
Family Name: Cyprinidae
Distribution: Myanmar
Size: Up to 1 inch
Color: Blue with white spots and orange fins
Care Level: Easy
Temperament: Peaceful
Lifespan: 3-5 years
Minimum Tank Size: 10 gallons
Tank Mate Compatibility: Nano fish


Celestial Pearl Danio Close Up

The Celestial Pearl Danio (Danio margaritatus) was discovered in Myanmar in 2006.

Interestingly they were first classified as Microrasbora which is where their nickname (Galaxy Rasbora) comes from.

However a year after their discovery they were reclassified as Danios.

They belong to the Cyprinidae family which hosts other small freshwater minnows including Rasboras and other Danios.

When images of this fish were first posted on Internet forums shortly after their discovery, many users assumed the photos were edited in some way until the first live specimens were produced. They are best know for their beautiful appearance and friendly behavior.

Celestial Pearl Danios are small, but they are very good at showing off! When kept in groups their little competitions and complex social behaviors can be fascinating to watch.

They will grow to a maximum of 1 inch long and have an average lifespan of 3 to 5 years.

Because they are still quite new to the aquarium community they are not very common. You might have to shop around with online retailers before you find some.

They are usually sold in groups of 6 for $10-$25.

Key Facts:

  • Experience Required: Recommended for beginners.
  • Nicknames: Galaxy Rasbora.
  • Color Forms: Blue with white spots and orange fins.
  • Size: 1 inches.
  • Tank Size: Minimum 10+ gallon.
  • Tank Temperature: 72-80°F.

Breeding Celestial Pearl Danios

Celestial Pearl Danio In Aquarium

It is very easy to breed Celestial Pearl Danios.

Courting is very common in a mixed gender group. Males will bow their heads and engage in elaborate displays when trying to impress a potential mate.

To encourage breeding conditions you can feed them a diet rich in krill and other high protein foods. You can use grindal worms if krill is not available.

A female in breeding condition develops a dark egg spot in front of her anal fin. Whereas males’ colors grow deeper and more radiant.

It is better not to let them breed in the main tank as other fish may eat the larvae and fry. Place your group in a breeding tank with stagnant water, a sponge filter and an air stone. The breeding tank must have leafy plants and a crop of Java Moss at the bottom to provide a safe breeding ground for your pair.

Your female’s abdomen will swell up when she is ready to lay her eggs. She can lay up to 30 eggs at a time (in clusters of 6 to 12).

The eggs appear as very tiny white spots in your Java Moss. Remove the parents from the tank as soon as they appear.

Eggs take up to 4 days to hatch and another 2 or 3 days to lose their yolk sacs. After this you can feed them powdered fry food, paramecium or infusoria.

At 3 months of age your juveniles will reach maturity and can be added to the main tank.

Celestial Pearl Danio Care Guide

Danio margaritatus

These fish are great for both beginners and experts but you need to remember that they are very delicate.

They can be injured or even killed if they get caught up in a fight.

It is important to keep the peace in your tank and provide plenty of hideouts for when a conflict breaks out.

These fish can also be literally scared to death (especially if there are not enough places to hide). Because of this you should never place them with particularly large or aggressive tank mates. Each individual in your group will need their own space to hide away so make sure you have enough hiding places around your tank.

Celestial Pearl Danio can also suffer from fin rot.

It can occur if the water temperature is too low or too high, or if the tank is dirty or poorly cycled.

The first sign of fin rot is a small lesion on any of the fish’s fins. Over time it progresses until the fins are covered in ulcers. It will spread to the rest of the body if left untreated.

Fin rot is treated with antibiotics but early detection is the key. Always seek a vet’s attention for any unusual marks, lesions, or bruises on any part of your fish’s body.

Diet and Feeding

Like many other Nano fish, the Celestial Pearl Danio is a micropredator.

Larval shrimp, insects, microworms and particulate algae are all on the menu. Every so often they will graze on plants and full sized algae.

They will eat just about anything you give them!

Anything you feed them must be able to sink to the bottom quick enough to avoid being stolen by greedy tank mates. It also needs to be small enough to fit into their mouth.

Quick sinking fish flakes or bottom feeder pellets are good options. So too are crushed algae wafers.

If you are looking for live options then Grindal worms are this fish’s favorite. They will also eat bloodworms and other small worms.

Krill is an excellent food that is packed with protein however it can be quite expensive.

Other good live foods include insect larvae, water fleas and larval brine shrimp.

Your Danios will occasionally nibble on the algae or plants in the aquarium but not in any significant amount.

Celestial Pearl Danios must be fed twice per day.

They should be give just enough food for them to finish in under 2 minutes. Change up the meals every day rather than feeding them the same thing over and over again.


Celestial Pearl Danios are very active during the day.

You will be pleased to know that they will be out in the open most of the time.

While they do engage in schooling behavior they also tend to split up from time to time. Schooling will occur if the fish feel distressed or threatened, if they have discovered a prime feeding location, or if they are just settling into a new aquarium.

Most of their social behaviors are based around mating and breeding. They will certainly not be on their best behavior when competing for mates. Males will flash their colors, bow their heads and dart in circles when a female is nearby. If other males get in the way they will chase them down and charge them.

Outside of their social groups they are extremely timid and too shy to really interact with other fish. You will never see them leave the bottom level of the tank.

School Of Celestial Pearl Danio

Aquarium Set Up

This species is endemic to Myanmar.

Here they live in stagnant pools that are alongside rivers and lakes.

They live at very high altitudes where the water temperature rarely exceeds 80°F. However, these locations still experience warm tropical temperatures. The water is soft with little to no flow and a neutral pH. The bottom (where the fish lives) is slightly murky from plant decay.

Above all these areas are packed with underwater plants of all kinds. The fish use these plants as both shelter and breeding ground.

To recreate these conditions in your tank you will need at least 10 gallons.

  • Water Temperature: 72-80°F
  • pH: 6.5-7.5
  • Water hardness: 2-10 dGH (5 is ideal)
  • Flow: None needed

You should use dark soft substrate that is enriched with fertilizers for your aquatic plants. Mud or dark colored sand is your best option.

If you want to add a bit of extra oxygen to your water then it is safer to use air stones rather than an air pump.

Your aquarium needs just enough decorations for your fish to feel at home. At the same time you do not want to overcrowd your tank and limit their swimming space.

A good option is to place your plants and decorations along the sides of your tank. This keeps an open space in the center for your fish to swim.

Decorations can include driftwood, logs, rocks and flowerpots filled with pebbles.

They will also need an underwater garden.

You can use just about any kind of plants you want but try to focus on background and middle-layer plants. This way you can leave your foreground open for swimming.

Try using Bucephalandra, Java Ferns, Temple Plant, and Hornwort as both a floating and a rooted plant. The deep red colors of Ludwigia plants also goes very nicely with such colorful fish. Read Top 15+ Best Floating Aquarium Plants For Beginners for more.

Tank Parameter Requirement
Minimum Tank Size 10 Gallons
Tank Type Freshwater planted
Temperature 72-80°F
pH 6.5-7.5
Hardness 2-10 dGH
Flow None
Substrate Dark sand or mud

What Size Aquarium Do They Need?

A group of 6 Danios need a 10 gallon tank.

You should add 2 gallons for each additional Danio after your first 6.

Celestial Pearl Danio Appearance

Celestial Pearl Danio Swimming

This exotic little fish gained their popularity because of their appearance.

When the photos first emerged online many assumed that they had been retouched.

However, those sparkling blue scales and pearly white spots are very real.

In order to be considered a Celestial Pearl a Danio must belong to the species Danio margaritatus and have the characteristic white dots over iridescent blue scales.

Males have midnight blue scales and deep red-orange fins. Whereas Females are slate grey with lighter orange fins.

Their dots can be white, cream or even yellow. When caught in the light the fish looks as though someone has sprinkled glitter all over them.

Males also have a red underside and a red stripe on top of their heads. Females have golden undersides but lack the red stripe.

Celestial Pearl Danios have a streamlined body that looks like a torpedo. They have a wide body, a thin abdomen and a slightly upturned snout.

You can expect them to grow to a maximum length of 1 inch but most will only reach 0.7 inches.

All 6 fins are bright red or deep orange in color and they are usually tucked when the fish is in motion. Even with such spectacular colors they can be difficult to spot. They have a set of dorsal fins, a caudal fin, pelvic fin, anal fin and 2 tiny pectoral fins.

In addition to the color there are several physical differences between males and females.

Females are smaller but their abdomens are round and appear swollen when she is ready to spawn. A female in breeding condition will develop a dark spot just before her anal fin.

Males have larger but thinner bodies and their colors are extremely striking when they are in breeding condition.

Suitable Tank Mates

Celestial Pearl Danios make great community fish!

In the wild they live among other Danios, Rasboras and other minnows.

The Harlequin, Glowlight and Chili Rasboras are 3 excellent Rasbora tank mates for your Danios. As for other Danios, the Zebra Danio and other Pearl Danio species work very well.

Guppies and Killifish will create a lovely accent for your Celestial Pearl Danio’s planted tank. Killifish in particular are also adapted to planted environments.

If you want to add more color then consider a group of Neon Tetras. These peaceful schooling fish will be no trouble for your Danios at all.

The Corydoras Catfish is an adorable and friendly bottom dweller that you can add to this setup. Oto Catfish are a good addition too.

Fully grown adult invertebrates are safe to keep too. Nerite Snails, Apple Snails, and Cherry and Amano Shrimp all have the added bonus of helping to keep your tank clean.

Just remember that Celestial Pearl Danios are easily frightened by fish that are much larger than they are. To be safe you should avoid any species that are over 3 inches long.

Because of this most Loaches are out, including the friendly Kuhli and Weather Loaches

The Pictus Catfish is also a bad choice because of their sharp spine.

All Gouramis and Cichlids must be kept away. Barbs are also a bad idea, with the exception of the Cherry Barb.

Keeping Celestial Pearl Danios Together

These fish should be kept in at least groups of 6.

When kept in a reasonably sized group they will school together when they need to feel safe, and establish social hierarchies and mini cliques within their school.

Although if you watch them closely you will notice they can get a little pushy with each another.

Most conflicts are about mating competition. You can reduce this by including more females than males in your group. Even numbered groups are much better than odd, but if you do have an odd numbered group then make sure the females outnumber the males.

History and First Sighting

When the Celestial Pearl Danio was first discovered in 2006 they took the Internet by storm. The first photos of the fish went viral among hobbyists, who wanted to know where they could get some for their tanks.

Due to this demand they were introduced into the ornamental pet trade immediately.

At the time their scientific name was Celestichthys margaritatus and they were known as the Galaxy Rasbora. However their physical similarities to Danios could not be ignored by the scientific community.

In 2007 an in depth analysis by the Smithsonian Tropical Research Institute discovered that the species harbored traits that Danios have, but Rasboras do not. They were then reclassified as Danio margaritatus in 2007.

As demand for this fish increased they attracted the attention of animal welfare groups. These groups mistakenly assumed that the fish only occurred in the Salween Basin.

The fish was falsely labeled extinct in the wild, but more populations were discovered scattered across the Lake Inle area. It was reclassified as least concern and today their populations remain stable.

Should You Keep The Celestial Pearl Danio? (Summary)

The beautiful Celestial Pearl Danio is worthy of any aquarium.

They are perfect for hobbyists of any skill level and are one of the best fish for aquascaping.

You do not need to a large tank to keep a good sized group. A tank as small as 10 gallons will fit 6 of them.

Their interesting behaviors will keep you on your toes and you will see them darting along the bottom levels of your tank.

As their scientific name suggests, they truly are a heavenly fish.

Which plants do your Celestial Pearl Danios have in their home? Let us know in the comments below…