Why do rummy nose tetras lose their red nose color with guppies?

Rummy nose tetras develop their best red coloration in soft, acidic water. When kept at pH 7.0 or higher to accommodate guppies, the red nose fades and the fish may stop schooling.

Can I keep rummy nose tetras and guppies together using peat filtration?

Peat or driftwood can soften water and lower pH into the 6.5-7.0 range that suits both species. Monitor pH closely, as rummies are sensitive to sudden shifts.

What temperature range works for both species?

75-77F is a good middle ground. Rummy nose tetras prefer 75-81F and guppies prefer 72-82F, so 75-77F sits comfortably within both ranges.

Can Guppy Live With Rummy Nose Tetra?

By Alex WalshLast reviewed Apr 18, 2026

It depends

Maybe, this pairing is tricky because rummy nose tetras need soft acidic water while guppies thrive in harder alkaline water.

Why

Rummy nose tetras grow to 2 inches and need soft, acidic blackwater (pH 5.5-7.0 ideal, tolerating up to 7.0).
Guppies stay at 2 inches and prefer hard, alkaline water (pH 7.0-8.0).
The temp overlap (75-82F) is reasonable, but the pH overlap is only the narrow range around 7.0.
Rummy nose tetras are sensitive to water quality fluctuations, which harder guppy tanks may not provide.
Fishkeepers report mixed outcomes , rummies sometimes fade or stop schooling in neutral-hard water.

Minimum shared tank

20 gallons

Shared temperature range

75-82°F

What could go wrong

Rummy nose tetras kept in pH 7.0+ long-term lose their distinctive red nose and may refuse to school, becoming withdrawn and prone to disease.

Gear for a shared tank

Sized for the 20 gallon minimum this pairing needs. Affiliate links — we earn a small commission if you buy through them.

AquaClear 30 Power Filter

Oversized filtration is what lets you stock two species together without water quality crashing. Rated for a tank slightly larger than the 20 gallon minimum.

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Eheim Jager 150W Thermostat Heater

Holds a steady temperature inside the 75-82°F window both species need.

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API Freshwater Master Test Kit

Keep ammonia, nitrite, and nitrate in check. Two-species tanks have more bioload and less margin for error than single-species setups.

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Better pairings to consider

This works if you maintain soft water (pH 6.5-7.0) with peat or driftwood and accept that guppies may show reduced color. If you prefer keeping guppies in hard water, house rummy nose tetras with other soft-water community fish instead.