Will my Neon Tetras school with Swordtails?

No, these species do not school together. Neon Tetras form their own mid-water school while Swordtails patrol the upper column and do not join tetra groups.

Can a group of female Swordtails reduce aggression toward Neon Tetras?

Yes, keeping two or three females per male distributes the male's attention and reduces the chasing behavior directed at other tankmates.

Is a 20-gallon tank enough for both species?

A 20-gallon tank provides the minimum footprint, but heavy planting and open swimming space matter as much as volume when mixing a small tetra with a larger active livebearer.

Can Neon Tetra Live With Swordtail?

By Alex WalshLast reviewed Apr 18, 2026

It depends

Sometimes, Neon Tetras and Swordtails coexist in 20+ gallons if there are multiple females per male Swordtail and plenty of planting, but male Swordtails can be pushy toward small fish.

Why

Neon Tetras stay at 1.5 inches and form loose schools in mid-water, while Swordtails grow to 4-5 inches and occupy the upper water column.
Swordtail males are active and can claim territory in the upper tank, which may stress tetras below.
Both species tolerate similar temperatures (72-81°F) and neutral pH (7.0), so water parameters are not the obstacle.
Swordtails prefer harder water than tetras do, but both adapt to community tank parameters without major issues.
The size difference means a single adult Swordtail outweighs a tetra by roughly 15 to 1, which shifts risk dynamics if aggression occurs.

Minimum shared tank

20 gallons

Shared temperature range

72-81°F

What could go wrong

A dominant male Swordtail may chase Neon Tetras during displays, causing chronic stress and color loss in the tetras even without physical contact.

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 72-81°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

In tanks where Swordtails thrive, consider peaceful community fish of similar size such as mollies, platies, or female Swordtails in a harem setup to reduce male pressure on smaller tankmates.