Madagascar Rainbowfish (Bedotia geayi): Care Guide

Madagascar Rainbowfish
Madagascar Rainbowfish. Loiselle P. V., Rodriguez D., CC BY 3.0

The Madagascar Rainbowfish (Bedotia geayi) is a captivating species native to the freshwater rivers and streams of Madagascar, particularly the island’s eastern regions. This species belongs to the Bedotiidae family and is highly valued in the aquarium trade for its striking iridescent colors that shimmer in shades of blue, yellow, and red under proper lighting, mimicking the vibrant hues of a rainbow. These fish exhibit a fascinating social behavior and prefer to dwell in groups, showcasing a hierarchical structure within their communities. They are omnivorous, feeding on a diet of small invertebrates, algae, and plant matter in their natural habitat. 

The Madagascar Rainbowfish has developed a unique adaptation to its environment; it can tolerate a range of water conditions, which is a testament to the resilience of this species. However, despite their adaptability, they face threats from habitat destruction and pollution, highlighting the importance of conservation efforts to preserve their natural ecosystems.

Common Name(s)Madagascar Rainbowfish
Scientific NameBedotia geayi
Temperature68-75°F (20-24°C)
SizeUp to 4 inches (10 cm)
Minimum Tank Size30 gallons (113 liters)
Food & DietOmnivorous; should be fed a varied diet of live, frozen, and flake foods
LifespanUp to 5 years
Water pH6.0-8.0
Tank MatesPeaceful; compatible with similarly sized and temperament species. Avoid aggressive or much larger fish.
BreedingEgg layer; relatively hard to breed in captivity. Requires specific water conditions and a well-planted tank.
Common DiseasesSusceptible to common fish ailments but no specific diseases are noted for the species. Good tank maintenance is essential.

Madagascar Rainbowfish Care

The Madagascar Rainbowfish is relatively hardy and can be easy to care for, making it a suitable choice for both novice and experienced aquarists. They thrive in a well-maintained tank with a temperature range of 68-77°F (20-25°C), and a pH level of 6.0-8.0. It’s important to provide them with a spacious tank to accommodate their active swimming habits, along with plenty of plants and hiding spaces to mimic their natural habitat. 

A varied diet of high-quality flake food, live, and frozen foods will help maintain their health and coloration. Regular water changes and monitoring of water parameters are essential to keep these fish healthy. Their relatively adaptable nature to various water conditions and their peaceful temperament make the Madagascar Rainbowfish a rewarding species to keep in a community aquarium.

Food & Diet

The Madagascar Rainbowfish is a beautiful and lively species that requires a balanced diet to maintain its health and vibrant colors. Here’s an overview of the ideal food and diet for Madagascar Rainbowfish:

Natural Diet

In the wild, Madagascar Rainbowfish primarily feeds on small insects, larvae, and plant matter. This omnivorous behavior suggests that a varied diet is essential for their well-being in captivity.

  • Flake Foods: High-quality flake foods can form the base of their diet, providing essential nutrients. Look for flakes that are formulated for tropical fish and contain both plant and animal ingredients.
  • Frozen and Live Foods: To mimic their natural diet, include frozen or live foods such as brine shrimp, bloodworms, daphnia, and mosquito larvae. These foods are excellent for promoting growth and enhancing colors. However, they should be given as a supplement to the main diet rather than the primary food source.
  • Vegetables: Since they are omnivores, introducing blanched vegetables like zucchini, spinach, or peas can be beneficial. These provide necessary fibers and help in digestion.
  • Pellets: Small-sized pellets can also be part of their diet, especially those that are designed to float or slowly sink, catering to the mid-water feeding habits of the rainbowfish.

Feeding Schedule

  • Frequency: Feed 2-3 times a day, offering only as much food as they can consume in a few minutes to prevent overfeeding and water quality issues.
  • Variety: Rotate their diet regularly to ensure they receive a range of nutrients. This not only keeps them healthy but also stimulates them mentally, making feeding time more engaging.


  • Water Quality: Overfeeding can lead to poor water quality, which can stress and harm the fish. Always remove uneaten food after feeding sessions.
  • Diet Adjustment: Pay attention to the fish’s behavior and condition. If you notice any health issues or changes in color, you may need to adjust their diet accordingly.

By providing a balanced and varied diet, you’ll help ensure your Madagascar Rainbowfish thrive in their aquarium environment, displaying their full spectrum of colors and natural behaviors.

Temperature & Water Parameters

The Madagascar Rainbowfish is a beautiful and colorful freshwater fish that’s native to the streams and rivers of Madagascar. To ensure their health and vibrant colors in an aquarium setting, it’s important to maintain the appropriate water conditions. Here are the key parameters you should monitor and maintain:

  • Temperature: The ideal temperature range for Madagascar Rainbowfish is between 72°F to 79°F (22°C to 26°C). This range simulates their natural tropical environment, promoting good health and activity.
  • pH Level: These fish thrive in slightly acidic to neutral water, with a pH range of 6.5 to 7.5. Consistent pH levels within this range help prevent stress and disease.
  • Water Hardness: The general hardness (GH) of the water should be kept within a range of 8 to 12 dGH. They can tolerate a wide range of hardness but prefer softer water that mimics their natural habitat.

It’s also crucial to regularly test the water for ammonia, nitrite, and nitrate levels, ensuring they remain at safe levels (ammonia and nitrite at 0 ppm, and nitrate as low as possible, ideally below 20 ppm). These fish are relatively hardy, but like all aquarium inhabitants, they benefit from stable conditions and a well-maintained environment. Keeping these parameters in check will help your Madagascar Rainbowfish thrive and display their most vibrant colors and behaviors.

Tank Size & Tank Setup

The Madagascar Rainbowfish are native to the rivers and streams of Madagascar and thrive in environments that mimic their natural habitats. Here’s a guide to the ideal tank size and setup for Madagascar Rainbowfish:

Tank Size

  • Minimum Tank Size: For a small group of Madagascar Rainbowfish, a minimum tank size of 30 gallons (around 114 liters) is recommended. These fish are active swimmers and enjoy having plenty of space to roam.
  • Group Size: They are shoaling fish that prefer to be in groups. Keeping them in groups of at least 5 to 6 individuals helps promote natural behavior and reduces stress, leading to healthier fish. Larger tanks will be needed for bigger groups to provide ample swimming space.

Tank Setup

  • Plants: These fish thrive in planted tanks that offer plenty of hiding spots and areas to explore. Use a variety of plants, including floating species, to provide shade and shelter.
  • Substrate: A dark substrate can help make the colors of the Madagascar Rainbowfish stand out more vividly.
  • Decoration: Incorporate driftwood, rocks, and caves to mimic their natural environment and provide additional hiding spaces.
  • Lighting: Moderate lighting is recommended to encourage plant growth without causing excessive algae. However, these fish do appreciate some shaded areas within the tank.
  • Filtration: A good filtration system is crucial to maintain clean and oxygen-rich water. However, the water flow should not be too strong as it may stress the fish.
  • Water Flow: Moderate water flow is beneficial for mimicking their natural habitat, which includes rivers and streams. Effective filtration is crucial to maintain clean water but avoid overly strong currents that can stress the fish.

Additional Tips

Regular water changes are important to remove toxins and keep the water parameters stable. A weekly change of about 20-25% is recommended, depending on the tank’s bioload.

Setting up a tank for Madagascar Rainbowfish requires attention to their specific needs for space, water conditions, and environment. With the right setup, these beautiful fish can be a joyful and colorful addition to your aquarium, displaying their natural behaviors and interactions.

Behavior & Temperament

The Madagascar Rainbowfish are known for their vivid colors and peaceful demeanor, these fish can add both vibrancy and harmony to a community aquarium. Understanding their behavior and temperament is crucial for anyone considering adding them to their aquarium. Here’s an overview:

Social Behavior

  • Community-Friendly: Madagascar Rainbowfish are generally peaceful and do well in community tanks with other species of similar size and temperament. They are not known to be aggressive towards other fish.
  • Schooling Fish: Like many rainbowfish species, Bedotia geayi prefers to be in groups. A school of six or more individuals is recommended to see their natural behavior and to keep them comfortable and stress-free.
  • Active Swimmers: They are known for their active swimming behavior, often seen exploring different levels of the aquarium but preferring the middle and top areas.


  • Peaceful: They maintain a peaceful demeanor towards tank mates and are rarely, if ever, aggressive. This makes them ideal candidates for a community tank.
  • Territorial Behavior: While generally peaceful, males can sometimes display mild territorial behaviors towards each other, especially in the presence of females. However, this seldom escalates to serious aggression if the tank is spacious enough and properly decorated to provide hiding spots and territories.
  • Interaction with Others: They tend to ignore other species and focus on interacting with their own kind, especially in a well-structured environment that mimics their natural habitat.

The Madagascar Rainbowfish is a delightful addition to any suitable community aquarium, bringing a dash of color and activity. Their peaceful nature, combined with a bit of natural territorial display among males, adds an interesting dynamic to the aquatic environment without the risk of serious aggression. Proper care, including the right social environment and tank conditions, will ensure these beautiful fish thrive and display their best colors and behaviors.

Are Madagascar Rainbowfish aggressive?

Madagascar Rainbowfish are generally considered peaceful and adaptable fish suitable for community aquariums. These fish tend to do well in groups and can be kept with other peaceful species of similar size. They are not typically aggressive towards other fish, making them a good choice for a mixed-species tank. However, like many fish species, individual temperaments can vary, and males may show some territorial behavior towards each other, especially during breeding periods. To minimize any potential aggression, it’s recommended to keep them in a spacious tank with plenty of hiding places and to maintain a group with a good male-to-female ratio.

How many Madagascar Rainbowfish should be kept together?

Madagascar Rainbowfish thrive in groups and their social behavior is a crucial part of their well-being in an aquarium setting. It is generally recommended to keep Madagascar Rainbowfish in groups of at least 6 to 8 individuals. This size of group helps in promoting natural behavior, reduces stress, and enhances their stunning colors and activity levels in the tank. In larger aquariums, keeping a bigger group is advisable to fully appreciate their schooling behavior and to ensure a more stable and harmonious environment.

Tank Mates

When choosing tank mates for Madagascar Rainbowfish, it’s crucial to select species that share similar water requirements and behavioral traits to ensure a harmonious environment. Here are some guidelines and suggestions for compatible tank mates:

  • Other Rainbowfish: Other species of rainbowfish, especially those that thrive in similar water conditions, can make excellent companions for Bedotia geayi. Ensure the tank is spacious enough to accommodate the active swimming behavior of these fish.
  • Tetras: Many tetras are peaceful and occupy the middle to upper levels of the aquarium, similar to Madagascar Rainbowfish. Look for species that are not too small to avoid them being seen as prey, such as Neon Tetras, Cardinal Tetras, and Rummy-nose Tetras.
  • Corydoras: These bottom-dwelling catfish are peaceful and can help keep the bottom of the tank clean. They are unlikely to compete for space or food with Madagascar Rainbowfish.
  • Loaches: Peaceful loaches like Kuhli Loaches or Zebra Loaches can be good companions, as they tend to occupy the bottom part of the tank and have a peaceful demeanor.
  • Livebearers: Livebearers such as Mollies, Platies, and Swordtails can be compatible with Madagascar Rainbowfish. They share similar water parameter requirements and are generally peaceful.
  • Dwarf Cichlids: Some dwarf cichlids, such as Apistogramma and some species of Rams, can coexist with Madagascar Rainbowfish, provided the tank is large enough and has plenty of hiding spots.
  • Gouramis and Bettas: Peaceful gouramis and Bettas can sometimes be housed with Madagascar Rainbowfish, but it’s essential to monitor for any signs of aggression or stress, as Betta fish can sometimes be territorial.

When planning your aquarium, consider the following to ensure compatibility and a stress-free environment for all inhabitants:

  • Water Parameters: Madagascar Rainbowfish thrive in water with a pH of 6.5-8.0 and temperatures between 68-75°F (20-24°C). Any chosen tank mates should thrive in these conditions as well.
  • Aquarium Size: Ensure your tank is large enough to accommodate the full adult size of all species and provide ample swimming space.
  • Habitat: Create a tank environment with plenty of plants, hiding places, and open swimming areas to mimic the natural habitats of these fish and reduce stress and aggression.

It’s also important to introduce new species gradually and monitor the aquarium closely for any signs of aggression or stress among the fish. Adjustments may be needed to ensure a harmonious community aquarium.

Common Disease & Health Issues

Like all aquarium fish, Madagascar Rainbowfish are susceptible to various health issues and diseases. Some of the most common problems that can affect Madagascar Rainbowfish include:

  • Ichthyophthirius multifiliis (Ich or White Spot Disease): This is a common parasitic disease in freshwater fish, characterized by white spots resembling grains of salt on the skin, gills, and fins. It is highly contagious and can be fatal if not treated promptly.
  • Fin Rot: This bacterial infection results in the fraying or rotting of the fish’s fins. It often starts at the edges of the fins, which may appear milky or ragged. Poor water quality and stress are significant contributors to fin rot.
  • Fungal Infections: Fungal diseases manifest as white or grayish fluffy growths on the skin, fins, or gills. These infections typically occur in fish that are already stressed or injured.
  • Velvet Disease (Oodinium): This is a parasitic infection caused by dinoflagellates, resulting in a dusty, velvet-like coating on the fish’s body. It can lead to breathing difficulties, lethargy, and clamped fins.
  • Bacterial Infections: Bacterial infections can lead to various symptoms, including ulcers, red streaks, bloating, and rapid breathing. These infections can stem from poor water conditions or injuries.
  • Ammonia Poisoning: High levels of ammonia in the tank, often due to inadequate filtration or overfeeding, can lead to ammonia poisoning. Symptoms include gasping at the water’s surface, red or purple gills, lethargy, and loss of appetite.

Prevention and Treatment:

  • Water Quality: Maintaining high water quality is crucial. Regular water changes, proper filtration, and monitoring of water parameters (ammonia, nitrite, nitrate, pH, and temperature) can prevent many diseases.
  • Quarantine New Fish: New arrivals should be quarantined in a separate tank for at least two weeks to prevent the introduction of diseases to your existing fish.
  • Diet: A varied and balanced diet helps in keeping the fish healthy and boosts their immune system.
  • Medication: Specific treatments are available for most diseases, including antiparasitic medications for ich and velvet, antibacterial treatments for bacterial infections, and antifungal treatments for fungal diseases. Always follow the instructions carefully and consider the impact on water quality and other tank inhabitants.

It’s important to act quickly at the first sign of illness, as early intervention can prevent the spread of disease and increase the chances of a full recovery for the affected fish.


Madagascar Rainbowfish is a fascinating species of freshwater fish native to Madagascar, known for its vibrant colors and active behavior. Breeding Madagascar Rainbowfish in an aquarium setting can be both rewarding and challenging. Here’s a comprehensive explanation of their mating behavior and a guide on how to breed them:

Mating Behavior

  • Social Structure: Madagascar Rainbowfish are schooling fish that thrive in groups. A healthy social structure, with a mix of both males and females, can encourage natural mating behaviors. Males often display vibrant colors and engage in showy displays to attract females.
  • Courtship Displays: During courtship, the male displays his brightest colors and performs a dance to attract a female. This dance includes rapid movements and flashing his fins to showcase his physical fitness and attractiveness.
  • Spawning Ritual: Once a female is interested, the pair will select a suitable spawning site, often among plants or in sheltered areas. The actual spawning is quick, with the female laying eggs and the male fertilizing them externally.

Breeding Guide

  • Set Up a Breeding Tank: Prepare a separate tank for breeding, around 20-30 gallons, with plenty of plants or spawning mops. The tank should have gentle filtration and a heater to maintain a temperature around 75-78°F (24-26°C).
  • Water Conditions: Ensure the water is slightly acidic to neutral (pH 6.5-7.5) with moderate hardness. Consistent water quality is crucial, so regular water changes are recommended.
  • Selecting Breeding Stock: Choose healthy, mature fish (about 6-12 months old) for breeding. A good ratio is two males for every three females to encourage natural selection and courtship behaviors.
  • Conditioning: Before introducing them to the breeding tank, condition the breeding stock with high-quality live or frozen foods like brine shrimp or bloodworms. This helps to stimulate spawning behavior.
  • Spawning: After introducing the fish to the breeding tank, monitor for spawning behavior. Spawning typically occurs in the morning hours.
  • Egg Care: Once eggs are laid, it’s often best to remove adult fish to prevent them from eating the eggs. The eggs will hatch in about 7-10 days depending on the temperature.
  • Rearing Fry: Feed the fry with infusoria or liquid fry food until they are large enough to eat baby brine shrimp. Frequent water changes and careful monitoring are necessary to ensure the fry grow healthily.

Additional Tips

  • Lighting: Moderate lighting conditions mimic their natural habitat and can encourage breeding behaviors.
  • Stress Reduction: Keep the breeding tank in a quiet location to reduce stress and promote successful spawning.

Madagascar Rainbowfish are relatively easy to breed compared to some other species, but attention to detail is key to raising healthy fry. By mimicking their natural environment and ensuring optimal water conditions, you can successfully breed and raise Madagascar Rainbowfish in your aquarium.

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