Tami River Rainbowfish

Glossolepis pseudoincisus

Rainbowfish
Reviewed by Guidarium Editorial DeskUpdated May 11, 2026

The Tami River Rainbowfish (frequently sold as the Millennium Rainbowfish) is a stunning, highly active shoaling species native to Papua, Indonesia. As they mature, males develop an intense, solid red coloration and a distinctively deep, arched back. They are fast swimmers that require plenty of open horizontal swimming space and do best in a mixed-sex school where males can display their best colors.

Tami River Rainbowfish At a Glance

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

Tami River Rainbowfish Tank Requirements

Minimum Volume110 L
Minimum Length90 cm
FlowModerate
Water TypeFreshwater Only
Must-Haves in the Tank
Plants - Densely covered
Stocking calculator

Will Tami River Rainbowfish fit in your tank?

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

Tami River Rainbowfish
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Tami River Rainbowfish Water Parameters

Temperature2428°C
pH78
Hardness515 dGH

Tami River 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)Fry Predator

Tami River Rainbowfish Varieties

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

Male (Millennium Red)

The highly sought-after male form. As they mature, males develop an intense bright red or deep orange color along with a significantly deeper, arched back. They frequently 'flash' a bright iridescent stripe on their head and back to show off to females.

Differs in 1 trait from base species

Also known as: Red, Millennium Male, Standard

TemperamentMostly Peaceful

Female

Females are much more slender than males and lack the intense red color, displaying a silvery-olive or yellowish hue instead. A proper school should contain a mix of sexes to diffuse male chasing and encourage natural behavior.

Differs in 2 traits from base species

Also known as: Silver, Wild Type Female

Adult Size8.5 cm
TemperamentPeaceful

Orange Albino (Xanthic Morph)

A commercially bred xanthic color morph where both sexes display a bright golden-orange coloration. They are peaceful, active, and require identical care to the wild-type millenniums.

Differs in 1 trait from base species

Also known as: Orange Albino, Gold, Xanthic

Behavior Traits
Hyperactive / Fast SwimmerJumper (Lid Required)Fry Predator

Tami River Rainbowfish Care Guide Summary

The Tami River Rainbowfish, scientifically known as Glossolepis pseudoincisus, belongs to the Rainbowfish family group. Adults reach a maximum size of approximately 10 cm and have a compressed 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 Tami River Rainbowfish requires a freshwater only aquarium with a minimum volume of 110 litres and a tank length of at least 90 cm. Water temperature should be maintained between 24°C and 28°C, with a pH range of 78 and a general hardness of 515 dGH. A moderate water flow is preferred.

The Tami River Rainbowfish is a rewarding species to keep, provided its core environmental needs are met. This species is available in 3 varieties: Male (Millennium Red), Female, and Orange Albino (Xanthic Morph). 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.

Tami River Rainbowfish Habitat Setup

When setting up an aquarium for the Tami River 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 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.

Tami River Rainbowfish Compatibility Notes

Classified as peaceful, the Tami River 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 Tami River Rainbowfish Is Actually For

Tami River 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 plants.

The most common mistake is buying Tami River 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.

Tami River Rainbowfish Recommended Tank Sizes

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

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Frequently Asked Questions About Tami River Rainbowfish

How big does Tami River Rainbowfish get?

Tami River Rainbowfish (Glossolepis pseudoincisus) typically reaches a maximum adult size of approximately 10 cm. They have a compressed body shape and a moderate growth rate.

What tank size does Tami River Rainbowfish need?

A minimum aquarium volume of 110 litres and a tank length of at least 90 cm are recommended for Tami River Rainbowfish. This ensures enough swimming space and helps maintain stable water conditions.

What water parameters does Tami River Rainbowfish need?

Tami River Rainbowfish thrives in freshwater only conditions with a temperature range of 24–28°C, a pH between 7 and 8, and a general hardness of 5–15 dGH. A moderate water flow is preferred.

Is Tami River Rainbowfish peaceful or aggressive?

Tami River 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 Tami River Rainbowfish should be kept together?

Tami River 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 Tami River Rainbowfish have any special tank requirements?

Yes. Tami River Rainbowfish benefits from plants - densely covered in the aquarium. These features help replicate their natural habitat and promote overall health and well-being.

Does Tami River Rainbowfish need a lid on the tank?

Yes. Tami River 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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