Celestial Pearl Danio (Galaxy Rasbora): Complete Care Guide

Celestial Pearl Danio
Celestial Pearl Danio
Dr. Mollie Newton
Published by Dr. Mollie Newton PHD| Senior Editor
Last updated: March 3, 2024
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Desiring to bring a bit of heavenly elegance to your fish tank? Search no more! The celestial pearl danio, which is termed Galaxy Rasbora or Microrasbora sp. “Galaxy,” is your ideal choice. These small freshwater jewels, originating from Southeast Asia, captivate aquarium lovers globally with their striking hues and shimmering spots.

Quick Summary

  • Known for iridescent blue spots resembling stars.
  • Peaceful, active swimmers exploring middle and upper tank levels.
  • Social creatures that prefer living in large groups.

Origin and Habitat

The celestial pearl danio (Danio margaritatus), is a small freshwater fish that can be found in the natural habitats of Myanmar and Thailand. These beautiful fish are typically found in shallow, slow-moving streams and rice paddies. Let’s explore their distribution and habitat in more detail.

Natural Habitat

In the wild, these colorful fish can be found in streams and ponds with dense vegetation and sandy substrates.

The dense vegetation not only offers a beautiful natural habitat for them but also provides essential hiding spots. These hiding spots are crucial for their survival as they help protect the celestial pearl danios from potential predators.

Moreover, the plants in their environment serve another important purpose – they act as a source of food. Celestial pearl danios are omnivorous, meaning they eat both plant matter and small invertebrates. The vegetation in their natural habitat provides them with a diverse range of food options, including algae, small insects, and other tiny organisms that live among the plants. This variety in their diet ensures that they receive all the necessary nutrients to stay healthy and thrive.

The sandy substrate found in their environment also plays a significant role in their well-being. It provides a suitable base for the aquatic plants to anchor themselves and grow, creating a stable ecosystem for the celestial pearl danios. Additionally, the sandy substrate allows the fish to exhibit their natural behaviors, such as sifting through the sand in search of food particles or creating small depressions for spawning.

Water Flow and Temperature

Celestial pearl danios thrive in water temperatures between 72°F and 79°F (22°C – 26°C). This range allows them to remain comfortable and active throughout the day. They prefer slightly acidic to neutral pH levels ranging from 6.5 to 7.5.

The slow-moving streams where these fish reside offer just the right amount of water flow for them to navigate easily without being swept away by strong currents. The calm waters allow them to swim gracefully while still having enough flow to bring nutrients and oxygen.

Group Behavior

These vibrant little fish are social creatures that enjoy living in large groups. Being part of a group provides them with safety in numbers as well as opportunities for breeding and establishing hierarchies within their community.


The celestial pearl danio’s preference for large groups stems from their natural instincts for survival. By staying together, they can better detect potential threats and reduce their individual risk of predation.

Appearance & Behavior

Celestial Pearl Rasbora (Galaxy Rasbora)
(1)Celestial Pearl Rasbora (Galaxy Rasbora)

The celestial pearl danio, also known as the galaxy rasbora, is a small and captivating fish that will bring an otherworldly charm to your aquarium. Let’s delve into their appearance and behavior to understand why they are such popular additions to fish tanks.

Striking Iridescent Blue Spots

One of the most remarkable features of the celestial pearl danio is its stunning appearance. These tiny creatures display iridescent blue spots on their bodies, resembling a sky full of twinkling stars. The shimmering spots create a captivating effect as light reflects off them, adding a touch of celestial beauty to any tank.

Colorful Males with Long Fins

In this species, males steal the show. They boast vibrant hues that surpass those of their female counterparts. Their fins are also longer and more elaborate, enhancing their overall elegance. Watching these colorful males gracefully glide through the water is like observing shooting stars in motion.

Peaceful and Active Swimmers

Celestial pearl danios are peaceful by nature, making them excellent community tank inhabitants. They are active swimmers who prefer exploring the middle and upper levels of the aquarium. Their constant movement adds liveliness to the tank environment while creating an enchanting spectacle for observers.

Shoaling Species

These delightful fish thrive when kept in groups. To ensure their well-being and happiness, it is recommended to keep at least six celestial pearl danios together. Being shoaling species, they feel more secure when surrounded by their companions. Observing a group of these graceful swimmers moving harmoniously through the water creates a mesmerizing sight reminiscent of constellations dancing in unison.


Celestial pearl danios, also known as galaxy rasboras, are small and colorful freshwater fish that can bring life and vibrancy to any aquarium. These beautiful fish have a lifespan of up to five years when given the proper care and attention.


To ensure their well-being and longevity, it is important to regularly monitor the water parameters in their tank. This includes checking the temperature, pH level, ammonia, nitrite, and nitrate levels. By keeping these parameters within the appropriate range, you can create an optimal environment for your celestial pearl danios to thrive.

Tank Requirements

Woman Setting Up A Fish Tank
Woman Setting Up A Fish Tank

Providing the right care and tank requirements for your celestial pearl danio is crucial to ensure their health and well-being. Let’s dive into the details:

Tank Size

It’s important to provide enough space for your celestial pearl danios to swim freely. A minimum tank size of 10 gallons is suitable for a small group of 5-7 fish. However, if you plan on keeping a larger school of these vibrant creatures, opt for a minimum tank size of 20 gallons to accommodate around 8-15 fish comfortably.


Choosing the appropriate substrate plays a significant role in creating an ideal environment for your celestial pearl danios. Opting for dark-colored fine sand mimics their natural habitat and enhances their vibrant colors. This type of substrate also allows them to explore and sift through it naturally.

Water Temperature

Maintaining the right water temperature is crucial for the well-being of celestial pearl danios. They thrive in temperatures ranging from 71 to 78°F (22-26°C). It’s also essential to ensure slow-moving water flow within the tank as these fish are not accustomed to strong currents.


Maintaining optimal water parameters is vital for the overall health of your celestial pearl danios. Aim for a pH level between 6.5 and 7.5, which falls within their preferred range.

Water Hardness

Water hardness is an important factor to consider when keeping celestial pearl danios. These small, colorful fish are native to Southeast Asia and prefer slightly acidic to neutral water conditions.

The ideal water hardness for celestial pearl danios is between 5 and 12 dH (degrees of hardness). This range ensures that the water is not too soft or too hard for these delicate fish. Maintaining the proper water hardness is crucial for their overall health and well-being.


To achieve the desired hardness level, you can use a water conditioner or add specific minerals to your aquarium water. Regular testing of the water hardness is recommended to ensure it remains within the appropriate range for celestial pearl danios.


A filter is not necessary for celestial pearl danios, but it is highly recommended. While these small and peaceful fish can tolerate a wide range of water conditions, including varying levels of hardness, having a filter in their tank can greatly improve their overall health and well-being.

A filter helps to maintain water quality by removing debris, excess food, and fish waste, which can quickly accumulate and lead to poor water conditions. It also helps to aerate the water, ensuring a constant supply of oxygen for the fish.

…a filter can help to establish and maintain a stable nitrogen cycle in the aquarium.

In addition, a filter can help to establish and maintain a stable nitrogen cycle in the aquarium. This cycle is essential for the breakdown of harmful ammonia, which is produced by fish waste and can be toxic to aquatic life. By providing a biological filtration system, a filter helps to convert ammonia into less harmful substances, such as nitrites and nitrates.


Proper lighting is essential both for the growth of live aquatic plants, and to showcase the stunning colors of celestial pearl danios. Aim for moderately bright lighting using high-quality LED lights. This will provide the necessary illumination without causing excessive stress or promoting algae growth.

Heavily Planted Tanks with Hiding Spots

Creating a natural environment for your celestial pearl danios is essential. These fish thrive in heavily planted tanks that mimic their natural habitat. Dense vegetation, such as Java moss or Amazon swords, provides hiding spots where they can retreat when feeling stressed or threatened. Live plants (even floating plants) help maintain water quality by absorbing nitrates and providing oxygen.

Tank Mates

A Galaxy Rasbora and Cherry Shrimp Enjoying the Aquatic Plants
(2) Galaxy Rasbora and Cherry Shrimp

It is essential to consider their peaceful nature and small size. These beautiful tropical fish get along well with other small, peaceful community fish such as tetras or guppies. However, it’s crucial to avoid keeping them in the same tank with aggressive or fin-nipping species like barbs or cichlids. Let’s explore some key points to keep in mind when selecting tank mates for your celestial pearl danios.

Compatibility with Peaceful Community Fish

Celestial pearl danios are small, peaceful fish that are loved by many aquarium enthusiasts. They have a calm demeanor and get along well with other fish in a community tank. It is important to choose tank mates that have similar water conditions and behavior to ensure a harmonious environment.

One great choice for companions is tetras, such as neon tetras or ember tetras. These fish are similar in size and temperament to celestial pearl danios, making them compatible tank mates.

Another option is guppies, which also coexist peacefully with celestial pearl danios. Guppies come in a variety of vibrant colors, adding a beautiful touch to the aquarium. When choosing tank mates for celestial pearl danios, it’s important to consider their peaceful nature and create a balanced community that will thrive together.

Avoiding Aggressive Fish Species

To ensure the well-being of your celestial pearl danios, it’s best to steer clear of aggressive fish species that may harm them or cause stress. Aggressive fish tend to nip at fins or dominate their tank mates, disrupting the tranquility of the aquarium environment. Barbs and cichlids fall into this category and should not be housed together with celestial pearl danios.

Tank Size Considerations

When you are thinking about which fish to keep with your celestial pearl danios, it’s important to choose tank mates that will get along well. One of the key factors to consider is the size of the tank. Although celestial pearl danios can live happily in a 10-gallon tank, giving them more space can have a positive impact on their overall health and happiness. When fish have more room to swim and explore, they tend to be less stressed and more active.


Having a larger tank also helps to reduce the chances of territorial disputes among the different fish in the aquarium. Celestial pearl danios are generally peaceful fish, but they can become territorial if they feel cramped or if there are too many fish in a small space. By providing them with a larger tank, you give them the opportunity to establish their own territories and reduce any potential conflicts.

Creating an Attractive Display

Mixing different color variations of celestial pearl danios can create a visually appealing display in your aquarium. Their vibrant colors range from deep reds to bright blues and whites. By combining different color morphs within a school of celestial pearl danios, you can achieve a stunning and eye-catching effect that adds beauty to your aquatic landscape.


Celestial pearl danios are relatively small fish, and in tanks with larger bottom-dwelling species, they may face challenges. To ensure their nutritional needs are met, avoid housing them with large fish that could outcompete them for food. Providing a balanced diet of high-quality flakes or pellets supplemented with occasional treats like brine shrimp ensures the overall health and vitality of your celestial pearl danios.

Diet and Feeding

Fish flake food
Fish flake food

Celestial pearl danios are easily adaptable eaters that happily accept various types of food. Their diet can include flakes, pellets, and frozen or live foods. These little fish are not picky, making them a pleasure to feed.

To ensure a well-rounded diet for your celestial pearl danios, it is recommended to supplement their meals with small live or frozen foods such as daphnia or brine shrimp. These options provide additional nutrients and mimic the natural prey items they would encounter in the wild. Adding these treats to their regular feeding routine can enhance their overall health and vitality.

It is best to offer small portions multiple times a day rather than one large meal. This approach prevents overeating and helps maintain water quality in the aquarium. By dividing their meals into smaller servings throughout the day, you ensure that each fish has an equal opportunity to consume enough food without creating excess waste.

Observing the feeding behavior of your celestial pearl danios is crucial for ensuring all individuals receive adequate nutrition. Some fish may be more dominant during feeding time, outcompeting others for food. To address this issue, consider implementing some strategies:

  1. Scatter food across different areas of the tank: This encourages all fish to explore and find their share of the meal.
  2. Use sinking pellets: These sink slowly, giving less dominant fish a chance to reach them before they are devoured by faster swimmers.
  3. Monitor individual behavior: Watch out for any signs of malnutrition or weight loss in specific individuals and adjust feeding strategies accordingly.

Remember that maintaining a balanced diet is essential for the overall health and longevity of your celestial pearl danios. Providing them with high-quality commercial foods supplemented with occasional live food or frozen treats ensures they receive all necessary nutrients.


Galaxy Rasboras, also known as Celestial Pearl Danios, are small freshwater fish that are native to Southeast Asia. While they are generally hardy and easy to care for, they can still be prone to certain health issues. It is important for aquarium owners to be aware of these common health problems in order to provide the best care for their Galaxy Rasboras.

  1. Ich (White Spot Disease): One of the most common health issues that Galaxy Rasboras can face is Ich, also known as White Spot Disease. This is a parasitic infection caused by the protozoan parasite Ichthyophthirius multifiliis. Infected fish will develop small white spots on their body and fins, which can lead to irritation and discomfort. To treat Ich, it is important to raise the temperature of the aquarium and use appropriate medications.
  2. Fin Rot: Another common health issue in Galaxy Rasboras is fin rot. This is a bacterial infection that affects the fins and can lead to the deterioration of the fin tissue. Fin rot can be caused by poor water quality, stress, or injuries. To prevent and treat fin rot, it is important to maintain clean water conditions, provide a balanced diet, and avoid overcrowding the aquarium.
  3. Swim Bladder Disorder: Galaxy Rasboras can also be prone to swim bladder disorder, which affects their ability to control their buoyancy. Fish with swim bladder disorder may have difficulty swimming upright or may float to the surface or sink to the bottom of the aquarium. This condition can be caused by various factors, including overfeeding, poor diet, or genetic predisposition. To prevent swim bladder disorder, it is important to provide a varied and balanced diet, avoid overfeeding, and maintain good water quality.
  4. Dropsy: Dropsy is a serious health issue that can affect Galaxy Rasboras. It is a symptom of an underlying condition, such as kidney or liver failure


Breeding celestial pearl danios can be a rewarding and exciting experience for fish enthusiasts. As an egg-scattering species, they require a separate breeding tank to ensure successful reproduction. Here are some important points to consider when breeding these beautiful fish:

  • Provide suitable spawning sites: To encourage egg-laying behavior, it is essential to provide fine-leaved plants or spawning mops in the breeding tank. These structures serve as ideal locations for the female celestial pearl danios to deposit their eggs.
  • Separate adult fish after spawning: Once the eggs have been laid, it is crucial to remove the adult fish from the breeding tank promptly. Adult celestial pearl danios have a tendency to consume their own eggs, jeopardizing the reproductive process. By removing them, you increase the chances of successful hatching.
  • Eggs hatch within 24 – 36 hours: After being laid, celestial pearl danio eggs typically hatch within a relatively short period. It is essential to monitor the tank closely during this time and ensure optimal water conditions for healthy development.

If you need more tips on how to breed Celestial Pearl Danios, watch this video below.

Breeding Celestial Pearl Danios | Galaxy Rasbora

Caring for the Fry

  • Feeding options for hatched fry: Once the fry have hatched, they will need appropriate nourishment to grow into healthy adults. Infusoria or commercially available liquid fry food can be used as initial food sources. These options provide necessary nutrients for their early stages of growth.
  • Introducing baby brine shrimp: As the tiny fry continue to grow, introducing live foods such as hatched brine shrimp can greatly enhance their nutritional intake. Baby or newly hatched brine shrimp are rich in proteins and essential nutrients, aiding in the healthy development of the celestial pearl danio fry.
  • Caring for the fry: Providing a suitable environment for the fry is crucial to their overall well-being. Ensure that water conditions are optimal, with appropriate temperature and pH levels. Regular water changes are also necessary to maintain cleanliness and prevent disease outbreaks.
  • The variety within the species: Celestial pearl danios come in various color variations, making them an attractive addition to any aquarium. From vibrant blues and reds to subtle pastels, there is a wide range of options available when selecting these captivating fish.

Breeding celestial pearl danios can be an enjoyable endeavor for aquarists looking to expand their fish family. By following these breeding guidelines and providing proper care for the hatched fry, you can witness the fascinating life cycle of these remarkable aquatic creatures.

Frequently Asked Questions

How many celestial pearl danios can you have in a 10 gallon tank?

In a 10-gallon tank, it’s recommended to keep a small group of 6 to 8 celestial pearl danios (also known as galaxy rasboras). This allows them to exhibit natural schooling behavior and maintain a comfortable environment.

Can you keep celestial pearl danios in a 5-gallon tank?

While celestial pearl danios are relatively small, a 5-gallon tank is considered too small to provide them with adequate space and water quality. It’s better to house them in a larger tank of at least 10 gallons to ensure their well-being.

Are celestial pearl danios nippy?

Celestial pearl danios are generally peaceful and not known to be nippy towards other fish. They tend to get along well with other peaceful community fish species. However, individual behavior can vary, so keeping an eye on interactions is advisable.

What is the celestial pearl danio habitat?

Celestial pearl danios are native to slow-moving streams and shallow rice paddies in Myanmar. Their natural habitat features dense vegetation, slow-flowing water, and shaded areas. Mimicking these conditions in their aquarium setup enhances their well-being.

Do celestial pearl danios need a heater?

Celestial pearl danios are comfortable in a wide range of temperatures, but they thrive in warmer water between 72°F to 78°F (22°C to 26°C). In most home environments, a heater is recommended to maintain a stable and suitable temperature for their optimal health and activity.

(1) Gedanken.welten, CC BY 3.0 https://creativecommons.org/licenses/by/3.0, via Wikimedia Commons
(2) Uccio D’Agostino, CC BY 4.0 https://creativecommons.org/licenses/by/4.0, via Wikimedia Commons

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