Betta care
The betta, or Siamese fighting fish, is the most popular fish in the hobby and the most routinely mistreated. It is sold in cups on shop shelves and marketed in tiny "betta cube" tanks and flower vases, which is exactly how not to keep one. Given a proper tank, a betta is a hardy, intelligent, characterful fish that lives for years and learns to recognise the person who feeds it. This guide is how to give it that tank, anchored on the one rule that matters most: at least 30 litres, heated and filtered.
Published 23 June 2026 · Last updated 23 June 2026 · 13 min read
The 30-litre rule, and the betta cube myth
The single most important decision in betta care is the tank, and it is the one shops get most wrong.
A betta needs a minimum of 30 litres, heated and filtered. More is better, and a single betta in a planted 30 to 60 litre tank is close to ideal. Work out the real volume of any tank you are considering with the tank volume calculator, because the figures printed on the box are often optimistic.
The cups, vases, and "betta cubes" bettas are sold in, often under 2 litres, are not tanks. They are too small to fit a heater or a filter, so the water sits cold and fouls within days, and they give the fish no room to swim or behave naturally. A betta in one survives rather than lives, and usually not for long.
The justification you will hear is that bettas "live in puddles in the wild". They do not. Wild bettas live in the warm, shallow, densely planted expanses of rice paddies and wetlands across Thailand and South East Asia: shallow, yes, but spread over a huge area, not a teacup. Their labyrinth organ, which lets them gulp air from the surface, helps them survive low-oxygen water for a while, but surviving poor conditions is not the same as thriving in them.
A 30-litre or larger tank gives stable warmth, room for gentle filtration, swimming space, and the long, healthy life a betta is capable of. It is also far easier to keep clean and stable than a tiny container, so it is the easier choice as well as the kinder one.
Setting up a betta tank
Once the tank is the right size, a few specifics make it a good betta home rather than just a fish tank.
A heater. Bettas are tropical and need warmth, so a heater is essential almost everywhere in Australia. A small 25 to 50 watt heater suits a 30-litre tank; size it with the heater wattage calculator. Trusted brands include Eheim, Aqua One, and Aquatop.
A gentle filter. A betta needs filtration, but it hates strong current: those long fins are hard to swim against, and a blasted betta hides in a corner and frays. Use a sponge filter, or baffle a hang-on-back filter's outflow so the water barely ripples. Cycle the tank before the betta moves in, exactly as for any tank (see how to cycle a new aquarium).
A lid, and an air gap. Bettas breathe air from the surface through their labyrinth organ, and they are determined jumpers. Keep a lid on the tank, and leave a few centimetres between the water and the lid so the layer of air the betta breathes stays warm and humid. Do not fill the tank to the brim.
Soft plants and hides, nothing sharp. Bettas tear their delicate fins on hard plastic plants and sharp decor, which then invites infection. Use live or silk plants and smooth ornaments, give the fish caves and planting to break up sightlines, and add a resting spot near the surface (a betta hammock leaf or a broad-leaved plant) where it can lie up near the air. Our planted tank basics guide covers easy plants, and the substrate guide the floor.
Water, temperature, and maintenance
Bettas are genuinely hardy on water chemistry but fussy about warmth. They suit a wide range of water, with a comfortable range of 24 to 28°C, a pH of 6.0 to 8.0, and soft to hard water alike, which means most Australian tap water suits them with nothing more than a dechlorinator. The one thing they will not forgive is cold: a betta kept cool becomes sluggish, stops eating, and sickens, which is the hidden cost of the unheated cube.
Maintenance is the same as any tank: a weekly 25% water change with temperature-matched, dechlorinated water (we like Seachem Prime, dosed with the water conditioner calculator), the glass wiped, and the substrate vacuumed. The bigger the tank, the more stable the water and the easier this is, which is one more reason the 30-litre tank beats the cube. Our water changes guide and maintenance schedule cover the routine.
Feeding a betta
Bettas are carnivores, built to eat small live prey at the surface, so their diet is high in protein, not the flake a community tank runs on. A good-quality betta pellet (brands like Hikari and New Life Spectrum make them) is the right staple, topped up with frozen or live treats such as bloodworms, brine shrimp, and daphnia a couple of times a week.
The cardinal feeding rule is small amounts. A betta's stomach is roughly the size of its eye, so two or three pellets once or twice a day is plenty: only as much as it clears in a minute or two. Overfeeding is the most common betta health mistake and causes bloating, constipation, and the swim bladder problems bettas are prone to. Fasting one day a week does them good. Our feeding guide has the full method.
Temperament and tankmates
The "fighting fish" name is earned. Male bettas are territorial and will fight, often to the death, so two males can never share a tank, and they should not even see each other through glass for long. Females are a little more tolerant and are sometimes kept in groups called "sororities", but these are unstable and best left to experienced keepers, not a first betta.
Many bettas are happiest alone, and a solo betta in a planted tank is a perfectly good setup, not a compromise. If you do want tankmates, it takes a larger tank (think 60 litres or more), and they must be peaceful, short-finned, and not brightly coloured, because a betta reads long fins and bright colour as a rival. Reasonable choices are bottom-dwellers and cleanup animals that keep out of its way, such as corydoras, kuhli loaches, and nerite snails.
Avoid, on the other hand: other bettas, guppies and other long-finned fish (the betta mistakes them for rivals and shreds them), fin-nippers like tiger barbs and serpae tetras (which shred the betta instead), and shrimp, which most bettas treat as food. Even a "safe" combination can fail, because individual bettas vary enormously in temperament, so add tankmates only when you have a backup plan to separate them. Check any planned community in the stocking calculator, and see our guide to stocking a community tank.
Common health problems
A betta in a warm, clean, properly sized tank is a hardy fish that rarely gets sick. Almost every common betta ailment traces back to cold water, dirty water, or overfeeding, so the cube is at the root of more betta illness than any germ. These are the ones to recognise.
Fin rot
Ragged, receding, or blackened fin edges, sometimes with a milky tinge. It is a bacterial infection that takes hold in poor water or after fin damage, and a long-finned betta is especially prone. The fix is almost always clean, warm, stable water: step up water changes, check the temperature, and mild cases heal on their own as the fins regrow. Persistent or fast-spreading cases may need an aquarium antibacterial treatment. See our common fish diseases guide.
Swim bladder and bloating
A betta that floats, sinks, or swims at an odd angle, often after a big meal, usually has a swim bladder problem brought on by overfeeding and constipation. Fast it for two or three days, keep the water warm, and many cases pass on their own. Prevent it by feeding small amounts and fasting one day a week. Persistent bloating with raised scales is a different and more serious problem (dropsy), covered in the diseases guide.
Ich (white spot)
Tiny white spots like grains of salt across the body and fins, with the fish flicking against surfaces. Ich is a parasite that often flares when a fish is chilled or stressed, another reason to keep the tank warm and stable. It is treatable, usually by gradually raising the temperature and using an ich treatment, and is one of the conditions a quarantine routine for new fish helps you avoid.
Fin biting and stress
Clean bites or chunks missing from the fins, often self-inflicted by a bored or stressed betta (it is different from the ragged edges of fin rot). Boredom, too strong a current, or a tank with nothing to explore are common causes. More planting, gentler flow, and a bigger or more interesting tank usually settle it. The bitten fins grow back as long as the water stays clean.
Choosing a healthy betta
Bettas come in a spread of colours and fin types: flowing veiltails and halfmoons, spiky crowntails, and the shorter-finned, more active plakats. The fancy long-finned forms are stunning but carry more fins to damage and to drag around, so the shorter-finned types are often the hardier, livelier pets.
Wherever you buy, look for an alert fish with intact, undamaged fins, good colour, and an interest in its surroundings. Pass on a betta that is pale, listless, sitting clamped-up on the bottom, or showing torn fins or white spots. The fish are usually sold in small cups, which are a holding container, not a verdict on the fish, but a betta that has clearly been suffering in one for a long time may already be in poor health.
Bettas in Australia
Bettas are sold in practically every Australian aquarium and pet shop, which is part of the problem: so are the cubes, vases, and bowls beside them. The fish are inexpensive and the marketing pushes the small containers hardest, so it takes a little resolve to walk past the cube and buy a proper tank instead.
The good news is that Australian tap water suits them almost everywhere. Bettas tolerate a wide range of hardness and pH, so the hard, alkaline water of Brisbane, Perth, and Adelaide and the softer water of Melbourne all work without adjustment, just a dechlorinator. The one universal requirement is heating: nowhere in Australia stays reliably in a betta's comfort range year-round indoors, so budget for a heater and an Australian-certified 240V model, never an uncertified import for something running constantly in water.
See the full betta care sheet for the data at a glance, and our guides on cycling a new aquarium, water changes, and common fish diseases, or browse the species directory.