Ramu Rainbowfish

Glossolepis ramuensis

Rainbowfish
Reviewed by Guidarium Editorial DeskUpdated May 11, 2026

The Ramu Rainbowfish is a beautiful, active schooling fish native to the Ramu River basin in Papua New Guinea. In the wild, they inhabit clear creeks with rocky and gravel bottoms. They are fast, active swimmers requiring plenty of lateral swimming space. Males develop stunning greenish-purple backs with orange stripes, while females remain silvery. Best kept in groups with a higher ratio of females to males.

Ramu Rainbowfish At a Glance

Adult Size7 cm
Body ShapeCompressed
Growth RateModerate
TemperamentMostly Peaceful
Water TypeFreshwater Only
Flow PreferenceModerate
Waste OutputLow
StockingSchool of 6+

Ramu Rainbowfish Tank Requirements

Minimum Volume150 L
Minimum Length100 cm
FlowModerate
Water TypeFreshwater Only
Must-Haves in the Tank
Smooth Gravel (Sensitive Barbels)Plants - Densely covered
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Will Ramu Rainbowfish fit in your tank?

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

Ramu Rainbowfish
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Ramu Rainbowfish Water Parameters

Temperature2429°C
pH78
Hardness515 dGH

Ramu Rainbowfish Temperament & Compatibility

Aggression LevelMostly Peaceful
3/10
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)

Ramu Rainbowfish Varieties

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

Standard / Unsexed

Typically sold as juveniles with subdued, silvery coloration. As they mature, sexual dimorphism becomes apparent. Must be kept in a shoal of 6 or more to feel secure.

Same care requirements as the base species

Also known as: Juvenile

Male

Males exhibit a greenish-brown or purplish back with narrow orange striping along the sides. They develop a deeper chest with age and will spar or display with other males. Provide plenty of hiding spots to break sightlines.

Differs in 2 traits from base species

Also known as: Adult Male, Show Male

TemperamentMostly Peaceful
Behavior Traits
Hyperactive / Fast SwimmerJumper (Lid Required)Aggressive to same species/look-alikes

Female

Females are slightly smaller, more streamlined, and have less vivid, silvery-drab coloration. Keeping a ratio of 2-3 females per male is recommended to disperse mating harassment.

Differs in 2 traits from base species

Also known as: Adult Female

Adult Size6 cm
TemperamentPeaceful

Ramu Rainbowfish Care Guide Summary

The Ramu Rainbowfish, scientifically known as Glossolepis ramuensis, belongs to the Rainbowfish family group. Adults reach a maximum size of approximately 7 cm and have a compressed body shape with a moderate growth rate. Classified as mostly peaceful, this species primarily occupies the surface and mid-level zones of the aquarium and produces a low level of biological waste.

To thrive, the Ramu Rainbowfish requires a freshwater only aquarium with a minimum volume of 150 litres and a tank length of at least 100 cm. Water temperature should be maintained between 24°C and 29°C, with a pH range of 78 and a general hardness of 515 dGH. A moderate water flow is preferred.

The Ramu 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.

Ramu Rainbowfish Habitat Setup

When setting up an aquarium for the Ramu 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 smooth gravel or rounded substrate to protect their sensitive barbels and dense planting to provide cover, break sightlines, and reduce stress. Keepers should note that a tight-fitting lid is essential, as this species is a known jumper.

Ramu Rainbowfish Compatibility Notes

Classified as mostly peaceful, the Ramu 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, 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 Ramu Rainbowfish Is Actually For

Ramu 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 smooth gravel.

The most common mistake is buying Ramu 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.

Ramu Rainbowfish Recommended Tank Sizes

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

Show 7 more tank sizes

Frequently Asked Questions About Ramu Rainbowfish

How big does Ramu Rainbowfish get?

Ramu Rainbowfish (Glossolepis ramuensis) typically reaches a maximum adult size of approximately 7 cm. They have a compressed body shape and a moderate growth rate.

What tank size does Ramu Rainbowfish need?

A minimum aquarium volume of 150 litres and a tank length of at least 100 cm are recommended for Ramu Rainbowfish. This ensures enough swimming space and helps maintain stable water conditions.

What water parameters does Ramu Rainbowfish need?

Ramu Rainbowfish thrives in freshwater only conditions with a temperature range of 24–29°C, a pH between 7 and 8, and a general hardness of 5–15 dGH. A moderate water flow is preferred.

Is Ramu Rainbowfish peaceful or aggressive?

Ramu Rainbowfish is classified as mostly peaceful with an aggression score of 3 out of 10. They are generally well-suited to peaceful community tanks.

How many Ramu Rainbowfish should be kept together?

Ramu 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 Ramu Rainbowfish have any special tank requirements?

Yes. Ramu Rainbowfish benefits from smooth gravel (sensitive barbels) and plants - densely covered in the aquarium. These features help replicate their natural habitat and promote overall health and well-being.

Does Ramu Rainbowfish need a lid on the tank?

Yes. Ramu 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 11, 2026
Last updated
May 11, 2026
Issues or corrections?
Contact the editorial team

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