Madagascar Rainbowfish

Bedotia madagascariensis

Rainbowfish
Reviewed by Guidarium Editorial DeskUpdated May 6, 2026

An energetic and colorful schooling fish from the flowing, shaded streams of Madagascar. Frequently misidentified in the aquarium trade as Bedotia geayi. Unlike Australian rainbowfish, they have an elongated, torpedo-like body. They are incredibly active, thrive in well-oxygenated water with some current, and are peaceful but voracious eaters.

Madagascar Rainbowfish At a Glance

Adult Size10 cm
Body ShapeFusiform
Growth RateModerate
TemperamentPeaceful
Water TypeFreshwater Only
Flow PreferenceModerate
Waste OutputMedium
StockingSchool of 6+

Madagascar Rainbowfish Tank Requirements

Minimum Volume150 L
Minimum Length90 cm
FlowModerate
Water TypeFreshwater Only
Must-Haves in the Tank
Driftwood (Digestion/Hiding)
Stocking calculator

Will Madagascar Rainbowfish fit in your tank?

Care guides tell you what Madagascar Rainbowfish needs, the next question is whether your tank can safely provide it. Test Madagascar Rainbowfish against your tank size, maintenance needs, and the fish you already keep before you buy.

Madagascar Rainbowfish
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Madagascar Rainbowfish Water Parameters

Temperature2226°C
pH6.58.5
Hardness820 dGH

Madagascar Rainbowfish Temperament & Compatibility

Aggression LevelPeaceful
2/10
Where They Swim
Surface
Mid-level
Bottom
Stocking Guidelines
Keep at Least6 fish
Max per TankNo limit
Can Live Alone?No — needs a group
Behavior Traits
Hyperactive / Fast SwimmerJumper (Lid Required)Aggressive Eater (Starves shy fish)

Madagascar Rainbowfish Varieties

Each variety inherits the species defaults above. Only differences are highlighted.

Standard / Unsexed

Typically sold as juveniles before distinct sexual dimorphism appears. Best purchased in a group of 6 or more to allow a natural social hierarchy to form as they mature.

Same care requirements as the base species

Also known as: Juvenile

Male

Noticeably more colorful than females, featuring prominent bold red and black margins on their caudal (tail), dorsal, and anal fins. Males use these vibrant colors to display to females and spar (peacefully) with other males.

Differs in 1 trait from base species

Also known as: Adult Male

Adult Size12 cm

Female

Slightly smaller and more subdued in coloration, lacking the intense red and black fin banding seen in males. A mixed-sex school is highly recommended to encourage males to display their best colors.

Differs in 1 trait from base species

Also known as: Adult Female

Adult Size10 cm

Madagascar Rainbowfish Care Guide Summary

The Madagascar Rainbowfish, scientifically known as Bedotia madagascariensis, belongs to the Rainbowfish family group. Adults reach a maximum size of approximately 10 cm and have a fusiform body shape with a moderate growth rate. Classified as peaceful, this species primarily occupies the surface and mid-level zones of the aquarium and produces a medium level of biological waste.

To thrive, the Madagascar Rainbowfish requires a freshwater only aquarium with a minimum volume of 150 litres and a tank length of at least 90 cm. Water temperature should be maintained between 22°C and 26°C, with a pH range of 6.58.5 and a general hardness of 820 dGH. A moderate water flow is preferred.

The Madagascar Rainbowfish is a rewarding species to keep, provided its core environmental needs are met. This species is available in 3 varieties: Standard / Unsexed, Male, and Female. Each may differ slightly in size, temperament, or care needs, so it is worth checking the specific requirements of the variety you plan to keep.

Madagascar Rainbowfish Habitat Setup

When setting up an aquarium for the Madagascar Rainbowfish, a moderate water flow best suits their natural preferences. Because this species occupies the surface and mid-level zones, the aquarium layout should prioritise adequate surface area with floating cover to make them feel secure near the waterline and open swimming space in the centre of the tank for free movement. Useful additions include driftwood, which can serve as both a hiding place and a dietary supplement. Keepers should note that a tight-fitting lid is essential, as this species is a known jumper.

Madagascar Rainbowfish Compatibility Notes

Classified as peaceful, the Madagascar Rainbowfish is a schooling species that feels most secure in a sizeable group, where natural shoaling behaviour reduces stress and brings out their best colours. When choosing tankmates, shy or slow-feeding tankmates may be outcompeted at feeding time and their energetic swimming style may stress more sedentary or timid species. Selecting tankmates that favour different water layers from the surface and mid-level zones can help reduce competition and territorial overlap.

Who Madagascar Rainbowfish Is Actually For

Madagascar Rainbowfish is best for a fishkeeper who wants a species that can settle into a calmer community setup and can provide a keeper who can commit to a proper group of at least 6. It makes the most sense for a hobbyist who will actually build around its needs, especially driftwood.

The most common mistake is buying Madagascar Rainbowfish for looks first and only later discovering how its adult size, behavior, or bioload changes the whole tank plan. Another frequent problem is underestimating its social needs. A token pair or trio often behaves very differently from a real group.

Madagascar Rainbowfish Recommended Tank Sizes

Standard aquarium sizes that meet the minimum volume and length requirements for Madagascar Rainbowfish.

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Frequently Asked Questions About Madagascar Rainbowfish

How big does Madagascar Rainbowfish get?

Madagascar Rainbowfish (Bedotia madagascariensis) typically reaches a maximum adult size of approximately 10 cm. They have a fusiform body shape and a moderate growth rate.

What tank size does Madagascar Rainbowfish need?

A minimum aquarium volume of 150 litres and a tank length of at least 90 cm are recommended for Madagascar Rainbowfish. This ensures enough swimming space and helps maintain stable water conditions.

What water parameters does Madagascar Rainbowfish need?

Madagascar Rainbowfish thrives in freshwater only conditions with a temperature range of 22–26°C, a pH between 6.5 and 8.5, and a general hardness of 8–20 dGH. A moderate water flow is preferred.

Is Madagascar Rainbowfish peaceful or aggressive?

Madagascar Rainbowfish is classified as peaceful with an aggression score of 2 out of 10. They are generally well-suited to peaceful community tanks.

How many Madagascar Rainbowfish should be kept together?

Madagascar Rainbowfish is a schooling species and should be kept in groups of at least 6. Larger groups help distribute aggression and encourage natural schooling behaviour.

Does Madagascar Rainbowfish have any special tank requirements?

Yes. Madagascar Rainbowfish benefits from driftwood (digestion/hiding) in the aquarium. These features help replicate their natural habitat and promote overall health and well-being.

Does Madagascar Rainbowfish need a lid on the tank?

Yes. Madagascar Rainbowfish is a known jumper, and a tight-fitting lid or cover is essential to prevent escape. Even a small gap can be enough for a determined fish to leap out.

Editorial Review

Guidarium Editorial Desk

Reviewed against Guidarium care, stocking, and compatibility standards. Read the editorial policy.

Last reviewed
May 6, 2026
Last updated
May 6, 2026
Issues or corrections?
Contact the editorial team

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