Madagascar Rainbowfish (Bedotia madagascarensis): Ultimate Care Guide

The Madagascar Rainbowfish (Bedotia madagascarensis), also referred to as the Red-Tailed Silverside, was first documented by zoologist Jacques Pellegrin in 1907. The Madagascar Rainbowfish is endemic to Madagascar, an island off Africa in the Indian ocean. They are found in shady, peaceful areas of the Mananjary River, which makes its way east.

The Madagascar Rainbowfish is characterized by its strong torpedo-shaped body and light yellowish-brown color, which emits a glossy blue sheen. A parallel dark blue line runs across its body, and a second shorter, fainter line runs below the first. Male Madagascar Rainbowfish have outlined vibrant indigo-red fins and tails. Female Madagascar Rainbowfish will look like males with faintly colored or clear fins.

Deforestation has produced an overconcentration of the Eastern Mosquitofish at altitudes approximately 500 meters above sea level in the Mananjary River. As a result, predatory Eastern Mosquitofish are in danger of eradicating Madagascar Rainbowfish from their natural habitat. Unfortunately, Madagascar Rainbowfish are now listed as vulnerable on the IUCN List of Threatened Species.

Madagascar Rainbowfish
Madagascar Rainbowfish (Bedotia madagascarensis)

Madagascar Rainbowfish Care

The Madagascar Rainbowfish can make a beautiful addition to the proper freshwater aquarium. Aquarists can have the unique experience of caring for or reproducing a vulnerable fish breed.


The Madagascar Rainbowfish will require a tank temperature somewhere between 72.0 to 77.0°F.

Water pH

The Madagascar Rainbowfish requires PH conditions that range between 6.5-8.5. Aquarists should test the water regularly to ensure it stays within these parameters.

Madagascar Rainbowfish Size

The Madagascar Rainbowfish can grow to be 5.9 inches long. Smaller Madagascar Rainbowfish can average three to four inches in length.

Madagascar Rainbowfish Tank Size

The Madagascar Rainbowfish requires a tank accommodating at least six other companions. A 30-gallon tank may temporarily suffice for a group of juvenile Madagascar Rainbowfish. However, as the Madagascar Rainbowfish mature, they will require a 100–150 gallon tank.

Madagascar Rainbowfish Food & Diet

The Madagascar Rainbowfish is an omnivore that requires a combination of green vegetables and high-protein foods. Their natural diet is comprised primarily of insects and plant matter. In captivity, the Madagascar Rainbowfish can consume high-quality flakes and pellets. However, the Madagascar Rainbowfish does require a varied diet to maintain proper health. Madagascar Rainbowfish will consume live or frozen foods like bloodworms, tubifex worms, brine shrimp, glass worms, water fleas, or mosquito larvae.

Plant foods can include algae pellets, ground vegetables, or spirulina flakes. Madagascar Rainbowfish should be fed twice daily and given what they can consume within five minutes. 

Madagascar Rainbow Fish Lifespan

Madagascar Rainbowfish will typically live for up to five years. However, Madagascar Rainbowfish can live up to 11 years in an aquarium when provided with optimal care.

Madagascar Rainbowfish Tank Mates

Madagascar Rainbowfish are naturally social and should be kept in a group of at least six other Madagascar Rainbowfish. However, in the wild, they tend to remain in groups of 12, which may be ideal if tank space allows. Compared to other kinds of rainbowfish, they are relatively docile. Madagascar Rainbowfish are inclined to coexist peacefully with other fish who require similar water parameters and tank conditions, provided they are of similar size, activity level, and temperament.

Suitable tankmates include Australasian Rainbowfish, characids, peaceful cichlids, barbs, and catfishes. Avoid aggressive fish as they can threaten the peaceful Madagascar Rainbowfish or slow-moving fish that can become agitated by too much activity. Bettas, aggressive cichlids, Hatchetfish, invertebrates, and Killifish, are incompatible with the Madagascar Rainbowfish. Bear in mind; when keeping Madagascar Rainbowfish with other Bedotia species, there is a possibility that hybridization could take place.

Madagascar Rainbowfish Tank Setup

The Madagascar Rainbowfish requires a tank set-up reminiscent of the flowing rivers of Madagascar. Typically, Madagascar Rainbowfish are inclined to dwell in shaded, lush areas of streams where they seek out vegetation and insects to eat. Their tank should be assembled with multiple powerheads to mimic their preferred habitat and replicate gentle river currents. Tank water should be clean and well-oxygenated as Madagascar Rainbowfish are sensitive to changes in water quality.

Dark sand and gravel substrate should form the basis of the tank. Currents should flow through fine-leaved plants. Taxiphylum Barbieri (Java moss), Ceratophyllum, or Floating Nylon Mops are ideal when breeding. Tank rocks and bogwood should be provided to provide additional hiding places.

However, tank décor should not compromise open swimming space as Madagascar Rainbowfish are active. The tank should be provided with moderate lighting with some shady spots. Lastly, the tank lid must be secured as Madagascar Rainbowfish are strong swimmers who may inadvertently dislodge an unsecured tank cover.

How to Breed Madagascar Rainbowfish

When breeding, Madagascar Rainbowfish should have a minimum of a 24-inch spawning tank with a sponge filter. There should be one male for every two to three females of similar size in the tank. Provide enough vegetation, rocks, or wood so the females can take refuge when necessary, as male fish can become aggressive. Madagascar Rainbowfish tend to spawn continually for a week or more, and females can produce several brown eggs daily.

Eggs can be removed manually and can be found tethered to plants and substrates by threads. Madagascar Rainbowfish tend to abandon fries and eggs and pay little attention to their offspring. However, it’s still best to remove eggs and place them in a nursery tank. Eggs will hatch in about a week. In the early phases of life, fish fries are very sensitive to environmental fluctuations, and water changes are usually avoided for 2-3 weeks.

In the wild, such rainbow fries will take refuge in shallow parts of the river for some time before journeying to deeper waters. Fry will develop slowly and require liquid fry food until they can consume small pieces of baby brine shrimp. Madagascar Rainbowfish can be moderately difficult to breed, but it’s entirely possible to encourage spawning in captivity.    

Madagascar Rainbowfish Male and Female

Male Madagascar Rainbowfish have more vibrant, colorful markings on their fins and tail. Female Madagascar Rainbowfish tend to have fuller bodies, especially when carrying eggs.  

Madagascar Rainbowfish Disease

Madagascar Rainbowfish can fall victim to various health problems. However, most Madagascar Rainbowfish are relatively hardy, and frequent disease likely won’t be a problem in a well-kept aquarium. Still, even the most thoughtfully cared for fish can occasionally fall victim to illness. Therefore, it’s a good idea to have a basic knowledge of the signs and symptoms of common fish ailments to act quickly and intervene early. Some common diseases to look out for in Madagascar Rainbowfish include: 

White Spot Disease (ICH)

Ich is a prevalent condition found among Rainbowfish. The condition is brought about by a parasite that produces white patches along the body. Treatment involves administering medications such as Ich- X, performing necessary water changes, and addressing any secondary infections brought about by open lesions.

Gill or Skin Flukes

Gill or Skin Flukes are usually diagnosed with a skin scrape or gill biopsy performed by an aquatic veterinarian. Rainbowfish suffering from gill or skin flukes usually experience clamped fins and mucous covering their bodies. Appropriate water additives and hygienic tank water help counteract this condition.

Hole in the Head Disease

Rainbowfish experiencing this condition will usually develop a depression near the head and experience a loss of appetite and lethargy. Hole-in-the-head disease treatment will typically consist of antibiotics, but interventions may vary.

Velvet Disease

Velvet is a common skin and parasitic gill infection. Fish with Velvet may present a rusty film on the skin, continually itch on rocks or sand, breath heavily, or experience skin peeling in advanced stages. Treatment may involve treating tank water with copper sulfate or salt and increasing water temperature appropriately.

The best way to prevent disease in Madagascar Rainbowfish is to maintain water conditions and offer them a varied and nutritious diet. The more accurately the tank mimics a natural, filtered, oxygenated environment, the healthier the fish will remain. Other preventative measures include keeping Madagascar Rainbowfish with companions and adequate space to swim actively while offering hiding places where the fish can withdraw when stressed.

Such measures help prevent fish from becoming overwhelmed and will boost their immunity. Be mindful of water composition changes, including ammonium and nitrite levels in your aquarium. Understand that any new plants, substrate, fish, aquarium, or décor could potentially introduce pathogens and bacteria to the tank, and consistently check the water quality. Such basic interventions can help ensure Madagascar Rainbowfish thrive happily and healthily for years to come.

Where can I find Madagascar Rainbow Fish for Sale?

Madagascar Rainbowfish range in price from $5-20 (USD). Those planning to purchase these communal fish should acquire a group of at least six and expect prices to increase proportionally. When provided with the proper care, Madagascar Rainbowfish are a peaceful and beautiful addition to a freshwater aquarium.

Madagascar Rainbow Fish

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