Best Fish for a 3ft / 90cm (≈120 Litre) Aquarium

The 3ft tank is the community sweet spot - stable, affordable and big enough for several schools and a centrepiece fish.

Approx. volume	120 litres
Typical dimensions	90 × 38 × 45 cm
Weight when full	~150 kg full
Rough stocking	~20 small community fish + clean-up crew

Plan exact stocking →

How many fish fit in a 3ft / 90cm (≈120 Litre)?

As a safe guide, a 120-litre tank holds around 20 small community fish plus a few bottom-dwellers or shrimp, kept understocked with good filtration. Add fish slowly over several weeks and keep schooling species in groups of six or more. Our stocking calculator works out the exact numbers for your chosen fish.

Best community & schooling fish

Betta (Siamese Fighting Fish)

Min 19L · 7.0cm · Aggressive (males)

Neon Tetra

Min 40L · 3.0cm · Peaceful

Harlequin Rasbora

Min 40L · 4.5cm · Peaceful

German Blue Ram

Min 75L · 5.0cm · Peaceful

Guppy

Min 40L · 5.0cm · Peaceful

Cherry Shrimp

Min 20L · 4.0cm · Peaceful

Cardinal Tetra

Min 55L · 3.5cm · Peaceful

Glowlight Tetra

Min 45L · 4.0cm · Peaceful

Black Neon Tetra

Min 55L · 4.0cm · Peaceful

Ember Tetra

Min 30L · 2.0cm · Peaceful

Lemon Tetra

Min 55L · 5.0cm · Peaceful

Rummy Nose Tetra

Min 60L · 4.5cm · Peaceful

Bloodfin Tetra

Min 60L · 5.5cm · Peaceful

Diamond Tetra

Min 75L · 6.0cm · Peaceful

Endler Guppy

Min 30L · 3.0cm · Peaceful

Centrepiece & feature fish

Fancy Goldfish

Min 75L · 20.0cm · Peaceful

Molly

Min 75L · 10.0cm · Peaceful

Sailfin Molly

Min 110L · 13.0cm · Peaceful

Swordtail

Min 75L · 12.0cm · Peaceful

Lyretail Molly

Min 75L · 11.0cm · Peaceful

Pearl Gourami

Min 75L · 12.0cm · Peaceful

Moonlight Gourami

Min 110L · 15.0cm · Peaceful

Blue Gourami

Min 110L · 15.0cm · Semi-aggressive

Paradise Fish

Min 75L · 10.0cm · Aggressive

Bottom-dwellers & clean-up crew

Bronze Corydoras

Min 60L · 7.0cm · Peaceful

Bristlenose Pleco

Min 75L · 13.0cm · Peaceful

Corydoras Paleatus

Min 60L · 6.5cm · Peaceful

Albino Corydoras

Min 60L · 7.0cm · Peaceful

Panda Corydoras

Min 60L · 5.0cm · Peaceful

Julii Corydoras

Min 60L · 6.0cm · Peaceful

Sterbai Corydoras

Min 75L · 6.5cm · Peaceful

Pygmy Corydoras

Min 40L · 2.5cm · Peaceful

Habrosus Corydoras

Min 40L · 2.0cm · Peaceful

Frequently Asked Questions

How many litres is a 3ft / 90cm (≈120 Litre)?

A 3ft / 90cm (≈120 Litre) holds roughly 120 litres of water once you allow for substrate and the gap below the rim. Typical dimensions are about 90 × 38 × 45 cm.

How many fish can a 3ft / 90cm (≈120 Litre) hold?

As a rough guide, around 20 small community fish plus a clean-up crew, kept understocked with good filtration. Use our stocking calculator for your exact fish.

How much does a 3ft / 90cm (≈120 Litre) weigh when full?

About ~150 kg full including water, substrate and rocks, so always use a stand rated for the weight on a solid, level floor.

What is the best fish for a 3ft / 90cm (≈120 Litre)?

It depends on the look you want, but the species listed on this page all suit a 120-litre tank. Pick fish with matching water needs and add them slowly.

Other Tank Sizes

Nano (20-40 Litre)2ft / 60cm (≈75 Litre)4ft / 120cm (≈200 Litre)5ft / 150cm (≈300 Litre)6ft / 180cm (≈450 Litre)