Tank size · Freshwater

What size tank for a GloFish (zebra danio)? (20 gal minimum)

GloFish (zebra danio) (Danio rerio (engineered)) — adult 2.5″, slim-bodied, schooling.

The three sizes — minimum, good, ideal

TierTank sizeWhat it gets you
Absolute minimum20 US galSurvives adult life. No extras — no tankmates beyond the essentials, no aquascape that eats footprint.
Good30 US galRoom for a small community, decor, and parameter buffering. This is where most people should aim.
Ideal50 US galNatural-feeling space. Active swimmers stop pacing, schoolers school freely, aggression drops.

Length matters more than gallons here — a 30-gallon tall (24″ long) and a 30-gallon long (36″ long) hold the same water but support different fish. GloFish (zebra danio) needs at least 30″ of length.

Parameters at a glance

Temperature
6475 °F
pH
6.57.5
Adult size
2.5
Body type
slim

Why tank size matters for this species

GloFish (zebra danio) is a schooling species — keep at least 6 together. The tank-size minimum above assumes that group. A single or pair-only setup stresses the fish, dulls colour, and shortens lifespan.

GloFish (zebra danio) is an active swimmer. The 30″ minimum length is non-negotiable — they pace the front glass for hours in shorter tanks.

Source for the tank-size minimum

Yorktown Technologies care guide.

Next steps

People also ask

What is the absolute minimum tank size for a GloFish (zebra danio)?
20 US gallons as an adult, with a minimum footprint of 30″ long. Yorktown Technologies care guide.
Can I keep a GloFish (zebra danio) in a smaller tank when it's a juvenile?
Briefly, yes — fish stores often sell juveniles that haven't reached adult size yet. But you should plan, buy, and cycle the adult-minimum tank from day one. Upgrading mid-life stresses the fish and is far more expensive than buying the right tank up front.
Do GloFish (zebra danio) need to be in a group?
Yes — they're schooling. A group of at least 6 together. Single or pair-only setups stress them, dull their colour, and shorten their lifespan. Plan tank size for the school, not the individual.
What temperature and pH does a GloFish (zebra danio) need?
Temperature 64–75 °F, pH 6.5–7.5.

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