Tetra Care Hub: Schooling Behavior, Water, and Tank Mates
Tetras are peaceful, colourful schooling fish that shine in planted community tanks — but only when kept in real groups and given soft, stable water. This hub covers schooling numbers, water needs, the best and worst tank mates, feeding and the signs of a healthy shoal.
Quick answer
Tetras are small, peaceful schooling fish that need to be kept in groups of at least six — ideally more — in a cycled, planted tank around 23–27°C with soft to moderately soft, slightly acidic water. Give them calm tank mates, a varied diet and stable water, and they reward you with tight, active schooling and bright colour.
Tetras are peaceful, colourful schooling fish that shine in planted community tanks — but only when kept in real groups and given soft, stable water.
Why schooling numbers matter
Tetras are shoaling fish that feel safe in numbers. Kept in twos or threes they become skittish, hide, lose colour and may nip. In a proper group of six or more they spread out, swim confidently and show their natural behaviour. If you can, aim for eight to twelve of one species rather than a mixed handful of several — a single strong school looks and behaves far better than several weak ones.
Tetras only school properly in groups of six or more — small groups look scattered and nervous.
Water they thrive in
Most popular tetras — neon, cardinal, ember, rummynose — originate from soft, slightly acidic Amazonian water. They tolerate a range, but stability matters more than chasing an exact pH. Keep ammonia and nitrite at 0 and nitrate under about 20–40 ppm, with a weekly 20–30% water change. Neon and cardinal tetras in particular are sensitive to being added to an immature, uncycled tank, so let the tank settle first.
Choosing tank mates
Tetras suit peaceful community setups. Good companions include corydoras catfish, small rasboras, honey gouramis, otocinclus and dwarf shrimp. Avoid fin-nippers such as some barbs when kept in low numbers, and avoid anything large enough to eat them — angelfish, for example, may hunt small tetras like neons. Match water needs and temperament, not just looks.
Tetras suit peaceful community tanks — pair them with calm, similarly sized fish.
Feeding
Feed a quality micro-pellet or small tropical flake as the staple, topped up with frozen or live daphnia, brine shrimp, cyclops and micro-worms. Their mouths are tiny, so food must be small. Feed small amounts once or twice a day, only what they clear in about a minute. Varied food keeps their colour rich and supports the whole shoal's health.
Signs of a healthy shoal
A healthy tetra school is tight, active and evenly coloured, spending most of the day in mid-water. Watch for individuals that lag behind, hide constantly, fade badly, develop lumps or white spots, or breathe rapidly. Because tetras are small, a sick fish can decline quickly, so daily observation during feeding is your best early-warning tool.
Quick FAQs
How many tetras should I keep together? At least six of the same species, and eight to twelve is noticeably better. Bigger schools are calmer, more colourful and more natural.
Are tetras good for beginners? Yes, once your tank is cycled and stable. They are hardy in mature water but dislike being the first fish in a brand-new tank.
Can I mix different tetra species? You can, but each species schools best with its own kind. A single large school of one species usually looks and behaves better than several small mixed groups.
Do tetras need a heater? Most do. They are tropical and prefer a steady temperature in the low-to-mid 20s°C, so a heater keeps them stable year-round.