My rummy nose tetras lost their red color. Is the betta causing this?

Almost certainly. Rummy nose tetras lose their red nose within hours of stress, and a betta in the same tank is a constant stressor. Check water parameters and remove the stressor if you want the coloration back.

Can I keep rummy nose tetras in a planted 20-gallon with a betta?

A 20-gallon gives the school room to avoid the betta during the day, but the betta owns the top water column and the tetras cannot escape at night when they rest near the substrate. This setup usually fails within weeks.

Do rummy nose tetras or bettas need softer water?

Rummy nose tetras strongly prefer soft, acidic water (pH 5.5-7.0). Bettas tolerate a broader range (pH 6.5-7.5). Neither species thrives at the extremes of the other's preference, making compromise difficult.

What size school of rummy nose tetras could survive with a betta?

A school of 12+ in a heavily planted 30-gallon might give the tetras enough cover to coexist temporarily, but long-term success is not reliable. The betta's individual temperament is always the deciding factor.

Can Betta Fish Live With Rummy Nose Tetra?

By Alex WalshLast reviewed Apr 18, 2026

No, rummy nose tetras need soft acidic water and large schools in 20+ gallons, conditions that conflict with standard betta setups.

Why

Rummy nose tetras are among the most water-sensitive community fish, requiring soft, acidic water (pH 5.5-7.0) at 75-84°F. These conditions do not align well with standard betta setups.
Rummy nose tetras need groups of 8+ in a 20+ gallon tank to school properly, which conflicts with the smaller betta territories most keepers maintain.
A betta will view a school of rummy noses as either competitors for the mid-water column or as potential prey, and the tetras' schooling formation triggers territorial aggression in many bettas.
Rummy nose tetras lose their signature red nose coloration when stressed, making them a visible barometer of tank stress. A betta's presence almost always causes measurable stress in this species.

Minimum shared tank

20 gallons

Shared temperature range

76-82°F

What could go wrong

The rummy nose school will show persistent stress: fading red noses, loose schooling, and hiding near the bottom. Eventually the tetras will either die from stress-related illness or be picked off one by one as the betta's aggression escalates.

If you keep them in separate tanks

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 76-82°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

Bettas do well with corydoras, snails, and plecos; rummy nose tetras pair with cardinal tetras, neon tetras, harlequin rasboras, and corydoras in a planted soft-water community tank.