Galaxy Rasboras

Galaxy Rasboras are fascinating freshwater fish, also known as Celestial Pearl Danios. Showcasing their remarkable galaxy-like colors, they have emerged as a beloved choice among aquarium aficionados. These amicable fish require minimal upkeep, making them an outstanding pick for community aquariums.

An icon to represent level of difficulty to care for a fish type.

Care DIfficulty


An icon to represent temperament.



An icon to represent origin.



An icon to represent size.


1 inch (2.5 cm)

An icon to represent a fish's lifespan.


3 years

List icon.

Table of contents

Origin, Appearance, Size, and Lifespan

The Galaxy Rasbora, scientifically named Danio margaritatus, is a highly sought-after freshwater fish originating from the small ponds of Myanmar. They can be found predominantly in bodies of water that are well shaded with dense vegetation.

In their native habitat, Galaxy Rasboras are frequently found in tranquil, shallow waters abundant with aquatic flora. This plant life serves not only as a hideout but also as a food source, while the dark, pebble-lined bottoms help their dazzling colors to pop. Being a gregarious species, they thrive in schools of at least six, but it's not rare to spot them in groups of 20 to 30 or more.

Their natural environment includes cool, slightly hard, and mildly alkaline water. The temperature typically ranges between 73 to 79 degrees Fahrenheit (23 to 26 degrees Celsius), with a pH level of 7.0 to 7.5, and water hardness between 2 to 12 dGH. To mimic a similar environment in your aquarium, strive to maintain a consistent water temperature, employ an efficient filtration system, and incorporate live plants and smooth pebbles.

By accurately replicating the Galaxy Rasbora's natural habitat and ensuring appropriate water conditions, you'll be preparing your fish for a content and robust life in your aquarium.

Galaxy Rasboras are acclaimed for their captivating, pearly-blue bodies speckled with bright orange spots, giving them a star-studded, galaxy-like appearance. These radiant colors make them an alluring and noticeable addition to aquariums. Even though they are petite, reaching up to roughly 1 inch (2.5 cm) in length, their unique coloration and lively nature make them a preferred choice for those desiring a spirited, radiant aquatic display. These delightful fish elicit smiles from viewers as they briskly dart around the tank, making them an admired choice among hobbyists of all skill levels.

With appropriate care, Galaxy Rasboras can enjoy a lifespan of up to three years. As social creatures, they prosper in groups and are best kept in schools of at least six members. To foster their well-being and ensure a prolonged life in captivity, it's crucial to provide a densely planted aquarium with plenty of hiding spots, as well as a diverse diet comprised of quality flakes, pellets, and frozen foods.

Fun Facts

Having delved into the appearance and lifespan of Galaxy Rasboras, in this segment we'll spotlight some intriguing facts about these enchanting fish that make them a marvel in the aquarium hobby. From their distinctive coloration to their communal behavior, Galaxy Rasboras are brimming with surprises and are certain to captivate any aquarium enthusiast.

  • Cosmic camouflage: In nature, Galaxy Rasboras frequently swim with other similar-looking species, exploiting their comparable appearance. This semblance aids both species in amplifying their group sizes and disorienting predators, thereby enhancing their likelihood of survival.
  • Natural UV shield: Galaxy Rasboras possess a special pigment known as guanophore, which supports them in the shadowy, peat-stained waters they inhabit naturally. This pigment functions as a natural sunscreen, shielding the fish from damaging ultraviolet (UV) radiation that penetrates the water's surface.
  • Danio relatives: Despite their colorful presentation, Galaxy Rasboras belong to the same family as zebrafish (family Cyprinidae), which are famed for their striped bodies. Nevertheless, Galaxy Rasboras have evolved vibrant colors as a form of concealment and communication within their dimly lit homes.
  • Ability to modulate colors: Galaxy Rasboras can adjust the brightness of their colors based on their environment, emotional state, or health. In poorly lit conditions or during stressful periods, their colors may seem less vibrant. On the flip side, when they feel safe and healthy, their colors intensify, making them a standout in an aquarium context.
  • Schooling behavior: Galaxy Rasboras are schooling fish, meaning they prefer to swim in groups. This behavior not only provides them with a sense of security but also forms an impressive visual spectacle in an aquarium. Their coordinated movements and star-studded appearance can metamorphose a home aquarium into an enchanting underwater cosmos.

Armed with these fascinating insights about Galaxy Rasboras, you'll be more prepared to admire their beauty and intricacies in your aquarium. In the subsequent section, we'll offer guidance on tank setups, ensuring your Galaxy Rasboras have the perfect environment to flourish and flaunt their celestial charm.

Recommended Tank Setups

Each arrangement comprises the basic components—tank, filter, heater, lighting, substrate, and more—to guarantee that you can establish a suitable environment for Galaxy Rasboras and other compatible freshwater species in your aquarium. As you transition from a budget-conscious to a high-end setup, you'll also have increased options for personalization, aesthetics, and advanced functionalities. Galaxy Rasboras are a schooling species and should be kept in groups of at least six individuals to alleviate stress and ensure their well-being. Typically, Galaxy Rasboras are priced between $3 and $6 per fish, although prices can differ based on aspects such as size, quality, and availability.

Budget-friendly setup (around $200):

  • Tank: 10-gallon aquarium with a lid or glass canopy ($30 - $60)
  • Filter: Sponge filter or hang-on-back (HOB) filter rated for 10 gallons ($15 - $30)
  • Heater: 50 watt adjustable aquarium heater ($10 - $25)
  • Lighting: Basic LED aquarium light ($15 - $40)
  • Substrate: Cost-effective aquarium sand or small gravel ($5 - $15)
  • Decor: A couple of pieces of driftwood and stones, along with affordable live plants like Java Fern and Anubias ($15 - $35)
  • Fish: Minimum 6, maximum 10 Galaxy Rasboras ($20 - $40)
  • Thermometer: $2 - $8
  • Substrate Vacuum: $7 - $20
  • Fish Net: $1 - $7
  • Algae Scraper or Magnetic Cleaner: $3 - $15
  • Siphon and Bucket: $10 - $25
  • Test Kit: $10 - $45
  • Fish Food: $3 - $15
  • Water Conditioner: $3 - $12

Mid-range setup (around $350 - $600):

  • Tank: 10-20 gallon aquarium with a lid or glass canopy ($45 - $100)
  • Filter: Canister filter or top-grade HOB filter rated for the tank size ($50 - $125)
  • Heater: 50-100 watt adjustable aquarium heater ($20 - $40)
  • Lighting: LED aquarium light with adjustable settings for plant growth and color enhancement ($40 - $125)
  • Substrate: Nutrient-rich aquarium substrate designed for planted tanks ($15 - $35)
  • Decor: A blend of driftwood, stones, and live plants such as Amazon Swords, Java Fern, Anubias, and Cryptocoryne species ($30 - $70)
  • Fish: Minimum 6, maximum 15 Galaxy Rasboras ($20 - $45)
  • Thermometer: $2 - $8
  • Substrate Vacuum: $7 - $20
  • Fish Net: $1 - $7
  • Algae Scraper or Magnetic Cleaner: $3 - $15
  • Siphon and Bucket: $10 - $25
  • Test Kit: $10 - $45
  • Fish Food: $3 - $15
  • Water Conditioner: $3 - $12

High-end setup (above $750):

  • Tank: 20-30 gallon rimless aquarium with a glass canopy ($100 - $200)
  • Filter: Superior-quality canister filter rated for the tank size ($80 - $200)
  • Heater: 100-150 watt adjustable aquarium heater with an external temperature controller ($30 - $60)
  • Lighting: Advanced LED lighting system with customizable settings for plant growth, color enhancement, and day/night cycles ($120 - $250)
  • Substrate: Premium aquarium substrate designed for planted tanks, with added root tabs for additional plant nutrition ($25 - $50)
  • Decor: A combination of driftwood, stones, and live plants to create a natural aquascape, featuring plant species such as Amazon Swords, Java Fern, Anubias, Cryptocoryne species, and carpeting plants like Dwarf Hairgrass or Monte Carlo ($50 - $130)
  • Fish: Minimum 6, maximum 20 Galaxy Rasboras ($20 - $60)
  • Thermometer: $2 - $8
  • Substrate Vacuum: $7 - $20
  • Fish Net: $1 - $7
  • Algae Scraper or Magnetic Cleaner: $3 - $15
  • Siphon and Bucket: $10 - $25
  • Test Kit: $10 - $45
  • Fish Food: $3 - $15
  • Water Conditioner: $3 - $12

Keep in mind, these figures are mere recommendations. You should also consider other factors such as tank companions and individual fish temperaments when deciding how many Galaxy Rasboras to house in your aquarium. Prices may fluctuate depending on location, brand, and availability.

Set Up Your Tank

Previously, we reviewed the various tank setups for Galaxy Rasboras and their fellow inhabitants. With this information at your disposal, we can delve into the detailed procedure for assembling your aquarium. This guide will help you choose the best location for your tank, clean and ready the tank, install the essential equipment, and prepare the water through cycling to ensure a safe habitat for your fish. We'll also go over the correct method for acclimating your Galaxy Rasboras to minimize stress as they settle into their new environment. By adhering to these suggestions, you'll be crafting a vibrant aquatic ecosystem where your fish can thrive.

  • Step #1: First, you need to pick a prime location for your aquarium. This spot should be out of direct sunlight and away from heaters or drafty areas. It must be on a level, sturdy surface that can support the weight of a full tank. If your aquarium setup necessitates a stand, follow the manufacturer's guidelines to assemble it, then place the unfilled tank on top.
  • Step #2: Proceed to clean the tank. Rinse it with clear water (steer clear of soaps or chemicals) to eliminate any dust or foreign particles. You can then use a clean cloth or paper towel to wipe the inside. Rinse the substrate (sand or gravel) until the water becomes clear in a separate container, and then spread it evenly on the bottom of your tank, making a slight gradient towards the back to give a sense of depth.
  • Step #3: Before adding water to the tank, draft a layout for your aquarium. This includes the positioning of heaters, filters, and other equipment. This preliminary planning will make setting up and maintaining your tank easier. Install the filter and heater as per the manufacturer's instructions. If you are opting for a sponge or under-gravel filter, place it under the substrate prior to adding water.
  • Step #4: Begin to decorate your aquarium with pieces of driftwood, stones, and plants, ensuring you create enough hiding spots for your fish and maintain open swimming spaces. Take care not to position your decorations in a way that could potentially damage or hinder the operation of your equipment. You can secure plants to pieces of driftwood or stones to keep them in place.
  • Step #5: Fill your tank with water that's been treated with a water conditioner, especially if your tap water contains chlorine or chloramines. Use a clean plate or plastic bag on the substrate to reduce any disturbance while filling. Fill the tank until it is approximately 2/3 full. Attach your aquarium light to the hood or canopy as per the manufacturer's instructions. It might be beneficial to use a timer to maintain consistent light cycles, which are crucial for both fish and plants. Connect the heater, filter, and any additional devices (air pump, CO2 system) to power sources, and place the thermometer in a spot where you can easily check it.
  • Step #6: Top up the water, ensuring there's space between the water level and the top of the tank for oxygen exchange. Activate the filter, heater, and other devices. Adjust the heater as necessary while monitoring the water temperature. Allow the tank to cycle for 4-6 weeks to allow beneficial bacteria to develop and stabilize the water conditions. During this cycling period, you may use a bacterial starter culture to accelerate the establishment of beneficial bacteria. Regularly check the levels of ammonia, nitrite, and nitrate using an aquarium test kit.
  • Step #7: Once the tank has cycled and the water parameters are stable, it's time to introduce your Galaxy Rasboras. Start acclimating them to the tank's conditions by floating the unopened fish bag in the aquarium for about 15-20 minutes to equalize the temperature. Then, open the bag and add a bit of tank water. Continue adding small amounts of tank water every 5-10 minutes for at least half an hour to an hour. This will allow your fish to gradually adjust to the new water chemistry. Using a net, carefully transfer the fish from the bag to the tank, ensuring minimal stress and avoiding any exposure to the bag water.
  • Step #8: Once all your fish have been introduced, set a consistent feeding schedule, providing suitable quantities of high-quality food for your specific species. Carry out regular water changes (around 20-30% every week or two) and maintain the water parameters using a test kit. Keep a close eye on your fish for any signs of stress or illness, particularly in the initial weeks following introduction. If required, be ready to intervene, which may involve adjusting water conditions or consulting with a seasoned aquarist.

By following this comprehensive guide and the additional setup tips, you can establish a thriving underwater habitat that allows your Galaxy Rasboras and their tank mates to prosper.

Recommended Water Parameters

For the health and happiness of your Galaxy Rasboras, it's crucial to maintain particular water conditions within your tank. Here's what you should aim for:

  • Temperature: The water should ideally be between 72°F and 79°F (22°C and 26°C) for optimal comfort.
  • pH: Strive for a slightly acidic to neutral pH ranging from 6.0 to 7.0.
  • Hardness: Water that is soft to moderately hard (1-10 dGH) is best for these fish.
  • Ammonia, Nitrite, and Nitrate: Keep both ammonia and nitrite levels at 0 ppm, and maintain nitrate levels below 20 ppm.
  • Lighting: Moderate to subdued lighting is recommended, coupled with dense vegetation to create shadowed areas and mimic their natural habitat.
  • Water movement: These fish prefer calm to moderately moving waters, imitating their natural environments.

Regular testing and maintenance of your aquarium water are essential to keep the conditions stable.

Routine Water Maintenance

Performing regular water changes is essential for maintaining a healthy Galaxy Rasbora habitat. These changes help eliminate surplus nutrients, waste products, and potential toxins. Here's a proposed schedule:

  • Weekly water changes: Substitute 20-30% of the tank water every week.
  • Test water parameters: Regularly check pH, ammonia, nitrite, nitrate, and hardness levels.
  • Use a gravel vacuum: Clean the substrate during each water change.
  • Dechlorinate the water: If you're using tap water, treat it with a water conditioner before adding it to the tank.
  • Match temperature and pH: Make sure the new water matches the tank water in both temperature and pH.
  • Acclimate the fish: Allow your fish time to adapt to new conditions after water changes.Moreover, consider these additional tips to ensure your fish's well-being and maintain your aquarium's aesthetic appeal:
  • Monitor lighting duration: Maintain a consistent 8-10 hour photoperiod each day. Overexposure to light can result in excessive algae growth.
  • Plant maintenance: Trim live plants regularly to keep them healthy and attractive. Remove any dead leaves or plant matter to prevent water quality deterioration.
  • Filter maintenance: Clean or replace the filter media as per the manufacturer's instructions, usually every 4-6 weeks. To avoid disrupting the beneficial bacteria, refrain from replacing all filter media at once.

Diet and Feeding Schedule

Galaxy Rasboras are omnivorous, requiring a varied diet. Here are some feeding guidelines:

  • Flakes and pellets: Feed your fish high-quality flake or micro pellet food suitable for small tropical fish.
  • Frozen and live foods: Supplement their diet with live or frozen foods such as daphnia, micro worms, or brine shrimp.
  • Feeding frequency: Offer small quantities of food 2-3 times a day, ensuring you avoid overfeeding.

Stress and Diseases

Stressors such as inadequate water quality, incompatible tank mates, or unsuitable tank conditions can affect your Galaxy Rasboras. Identifying and managing these stressors is crucial:

  • Watch for stress signs: Keep a lookout for unusual behavior like hiding, lethargy, color loss, or rapid breathing, as these may indicate stress.
  • Check water quality: Regularly test your aquarium water to ensure it falls within the ideal parameters and maintain a clean environment through water changes.
  • Monitor tank mates: Ensure your Galaxy Rasboras are not being harassed or bullied by other fish in the tank. If necessary, remove any aggressive tank mates.
  • Create a suitable habitat: Supply ample hiding spots, suitable lighting, and an adequately sized tank.

Though Galaxy Rasboras are generally hardy, they are not immune to common fish diseases. Among these are:

  • Ich (white spot disease): An infectious parasitic disease, it causes white spots on the body and fins, lethargy, and loss of appetite. Treat Ich using aquarium salt or anti-parasitic medication and increase the water temperature to around 82°F (28°C).
  • Fin rot: A bacterial infection causing discolored or frayed fins and tail. Treatment involves partial water changes, aquarium salt, and antibacterial medication with erythromycin or tetracycline.
  • Velvet disease: A parasitic infection manifesting as a yellowish or brownish velvet-like coating on the fish's body. Treat with an anti-parasitic medication containing copper sulfate or formalin.
  • Swim bladder disease: This condition affects the fish's buoyancy. Treat by fasting the fish and offering them blanched peas. An antibacterial medication may be necessary in some cases.

By maintaining high-quality water, avoiding overfeeding, providing a balanced diet, quarantining new fish, and treating any illness signs promptly, you can help prevent diseases in your Galaxy Rasboras.


Breeding Galaxy Rasboras can be a rewarding experience for hobbyists, but it requires careful preparation:

  • Step #1: Set up a suitable breeding environment in a separate tank with a pH of around 6.0 to 7.0, a temperature of about 75°F (24°C), and soft water (1-5 dGH). Add hiding spots like plants for the fish's comfort.
  • Step #2: Choose healthy, mature male and female Galaxy Rasboras for breeding. The males are usually smaller and brighter than females.
  • Step #3: Prior to breeding, feed the chosen pair a high-protein diet of live or frozen foods to help them build up energy and strength.
  • Step #4: Encourage spawning by gradually raising the water temperature, reducing the lighting, and maintaining a natural day-night cycle. Including a spawning mop or fine-leaved plants can provide a place for egg deposition.
  • Step #5: After spawning, remove the breeding pair and keep the breeding tank in a dimly lit area, as the eggs and fry are sensitive to light. Eggs usually hatch within 24-48 hours, and the fry will begin to swim freely after several days. Initially, feed the fry infusoria or liquid fry food, then gradually introduce crushed flake food as they grow.
  • Step #6: Keep an eye on the fry's growth and development, and segregate them by size if needed to prevent larger fry from preying on the smaller ones.Breeding Galaxy Rasboras can provide a fascinating insight into their life cycle. With patience and the right conditions, your efforts will likely succeed.

Recommended Tank Mates

These are some top suggestions for tank mates for Galaxy Rasboras:

  1. Harlequin Rasboras
  2. Neon Tetras
  3. Endler's Livebearers
  4. Dwarf Gouramis
  5. Cherry Barbs
  6. Bristlenose Plecos
  7. Cherry Shrimp
  8. Amano Shrimp
  9. Celestial Pearl Danios
  10. Otocinclus Catfish

Avoid keeping them with large, territorial fish such as cichlids or angelfish, as these could harass or harm the Galaxy Rasboras. Monitor new additions to ensure they interact peacefully with your existing Galaxy Rasboras.


Galaxy Rasboras, known for their beautiful star-like pattern, are easy-to-care freshwater fish. They demand specific water parameters, a balanced diet, and a comfortable environment to live a healthy life in captivity. Given suitable conditions, they can live for up to five years and add a celestial sparkle to any aquarium. When choosing their tank mates, it's important to go for non-aggressive and peaceful species for maintaining harmony within the aquarium community. Breeding Galaxy Rasboras is a task that requires patience and optimal conditions but can be highly rewarding for dedicated aquarists. Galaxy Rasboras truly add a touch of the galaxy to your aquatic setup with their stunning colors and active behavior.

Frequently Asked Questions

What is the ideal tank size for Galaxy Rasboras?

For Galaxy Rasboras, a 10-gallon tank serves as a suitable home for a small group. A larger tank can provide better water stability and ample space for your fish to swim.

How many Galaxy Rasboras should be kept together?

Being a schooling fish, Galaxy Rasboras prefer to be in groups of at least 6 to 8. Larger groups will make the fish feel more secure and will allow them to exhibit their natural behaviors.

What water parameters do Galaxy Rasboras require?

The ideal water temperature for Galaxy Rasboras is between 72°F and 79°F (22°C and 26°C), the pH should be slightly acidic to neutral ranging from 6.0 to 7.0, and the water should be soft to moderately hard (1-10 dGH).

What do Galaxy Rasboras eat?

Being omnivorous, Galaxy Rasboras require a varied diet. A mix of high-quality flake or micro pellet food, supplemented with live or frozen foods like daphnia, micro worms, or brine shrimp, should be provided.

Are Galaxy Rasboras compatible with other fish?

Yes, Galaxy Rasboras are peaceful and can be kept with other small, non-aggressive fish. Ideal tank mates can include small tetras, other rasboras, dwarf gouramis, and cherry barbs.

How can I differentiate between male and female Galaxy Rasboras?

Males of the species are typically smaller and more brightly colored, especially during breeding season. Females are a bit larger with a more rounded body.

How long do Galaxy Rasboras live?

With proper care and ideal tank conditions, Galaxy Rasboras can live for up to 3 to 5 years.

How do I breed Galaxy Rasboras?

Breeding Galaxy Rasboras requires setting up a suitable environment in a separate tank with ideal water parameters, temperature, and plenty of hiding spots. It's crucial to feed the breeding pair a high-protein diet prior to breeding and to ensure the tank has subdued lighting.

Do Galaxy Rasboras require a planted tank?

Though it's not a strict requirement, a planted tank can benefit Galaxy Rasboras by providing them with hiding spots, improving water quality, and replicating their natural habitat.

Can Galaxy Rasboras change color?

Yes, Galaxy Rasboras may exhibit color changes due to stress, sickness, or changes in water conditions. If your Galaxy Rasboras seem to lose their color, it's important to check the water parameters and observe their overall health closely.