Best Fish for a Nano (20-40 Litre) Aquarium
Nano tanks are perfect for a single betta, a shrimp colony or a tiny school of nano fish. Stability is the challenge, so go slow and avoid messy or large species.
| Approx. volume | 35 litres |
| Typical dimensions | ~30-40 cm |
| Weight when full | 40-55 kg |
| Rough stocking | ~5 small community fish + clean-up crew |
How many fish fit in a Nano (20-40 Litre)?
As a safe guide, a 35-litre tank holds around 5 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)
Cherry Shrimp
Min 20L · 4.0cm · Peaceful
Ember Tetra
Min 30L · 2.0cm · Peaceful
Endler Guppy
Min 30L · 3.0cm · Peaceful
Betta
Min 19L · 7.0cm · Aggressive (males)
Sparkling Gourami
Min 30L · 4.0cm · Peaceful
Chili Rasbora
Min 20L · 2.0cm · Peaceful
Dwarf Rasbora
Min 20L · 2.5cm · Peaceful
Phoenix Rasbora
Min 20L · 2.0cm · Peaceful
Axelrod Rasbora
Min 30L · 2.0cm · Peaceful
Clown Killifish
Min 30L · 3.5cm · Peaceful
Pea Puffer
Min 20L · 2.5cm · Semi-aggressive
Licorice Gourami
Min 30L · 4.0cm · Peaceful
Celestial Pearl Danio
Min 30L · 2.5cm · Peaceful
Blue Velvet Shrimp
Min 20L · 4.0cm · Peaceful
Bottom-dwellers & clean-up crew
More coming soon.