The best 5 gallon (19 L) aquariums for 2026
Around 5 gallons (19 litres) is the practical floor for a stable, easy nano tank — big enough to hold parameters, small enough for a desk. These are the little tanks we rate for build and filtration, whether you want a betta, shrimp or a planted scape.
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Frequently asked questions
What fish can live in a 5 gallon tank?
A single betta is the classic choice, and a 5 gallon also suits a small shrimp colony or a few snails. Most schooling fish need more room to feel secure, so keep stocking light — a nano is about one centrepiece or a tidy invertebrate setup, not a crowd.
Is 5 gallons big enough for a betta?
Yes — 5 gallons is a comfortable minimum for a single betta, giving room to swim and enough water volume to keep parameters steady. Add a gentle heater and low-flow filter, since bettas dislike strong current, and you've got a healthy long-term home.
Do small tanks need a filter and heater?
Almost always. A small water volume swings in temperature and chemistry faster than a big one, so a heater keeps tropical fish stable and a gentle filter grows the bacteria that process waste. Skipping them makes a nano harder to keep, not easier.
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