Fish Tank Sizes

Neon tetra tank size

A 10 gallon holds a school of 8 to 11. A 15 or 20 gallon long meets the footprint Seriously Fish recommends.

Neon tetras are tiny, about 1.2 inches as adults, so volume is rarely the problem. What matters is a school of at least 8 and enough length to swim in a group. Seriously Fish gives a base of 60 x 30 cm (about 24 x 12 inches). A 10 gallon is 4 inches short of that but passes the stocking check with a note, which is why it is the most common first neon tank.

How many neon tetras fit in each tank

Counts are for a tank with nothing else in it, from the same model as the stocking calculator.

TankLength x widthMeets the footprintMost on their own
5 Gallon16 x 8 inUnder–
10 Gallon20 x 10 inCloseup to 11 *
15 Gallon24 x 12 inYesup to 16
20 Gallon Long30 x 12 inYesup to 21
20 Gallon High24 x 12 inYesup to 22
29 Gallon30 x 12 inYesup to 31
40 Gallon Breeder36 x 18 inYesup to 50
55 Gallon48 x 13 inYesup to 64
75 Gallon48 x 18 inYesup to 88
125 Gallon72 x 18 inYesup to 139

Footprint is the Seriously Fish minimum base of 24 x 12 in. “Close” is within 20%. * Fits by volume, but the footprint is under the recommendation.

Neon tetras schooling above corydoras catfish in a planted tank

Neon tetra at a glance

Adult sizeabout 1.2 in
Minimum base24 x 12 in
Temperature70 to 77°F
pH4.0 to 7.5
Group8 or more

Tank mates

They are peaceful and easy to keep with other small fish: ember tetras, rasboras, corydoras and small gouramis. Skip angelfish and anything with a mouth big enough to eat a one inch fish.

Seriously Fish: Generally peaceful community fish; best with similarly sized characins, small catfishes and non-predatory small-to-medium cichlids.

Check a neon tetra tank

Mixes with neon tetras that pass the check

  • 10 Gallon: a school of neon tetras

    8 × Neon tetra.

    68% stocked
  • 20 Gallon Long: neon tetras and panda corydoras

    10 × Neon tetra, 6 × Panda cory.

    95% stocked
  • 20 Gallon High: neon tetras and panda corydoras

    10 × Neon tetra, 6 × Panda cory.

    89% stocked
  • 40 Gallon Breeder: a big school of neon tetras with corydoras

    20 × Neon tetra, 8 × Bronze cory.

    79% stocked

Common questions

What size tank does a neon tetra need?

Seriously Fish gives a minimum base of 60 x 30 cm, about 24 x 12 in. The smallest standard tank that meets it is the 15 gallon.

What temperature and pH do neon tetras need?

70 to 77°F and a pH of 4.0 to 7.5, by Seriously Fish.

How big do neon tetras get?

About 1.2 inches (30 mm) as adults, by Seriously Fish.

Can neon tetras live in a 5 gallon tank?

No. A 5 gallon is 16 x 8 inches, well under the 24 x 12 inch base Seriously Fish recommends, and too short for a school to swim. Ember tetras or chili rasboras suit a 5 gallon better.

Gear for a neon tetra tank

Searches on Amazon for the right size. Check the tank size or flow rating on the listing before you buy.

10 gallon aquarium kitThe usual first neon tank.Heater, 50 WNeons like 70 to 77°F.Sponge filterGentle flow, and fry safe.Water test kitNeons are sensitive to new tanks.

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Sources: Seriously Fish. Scientific name Paracheirodon innesi.