Betta (Siamese fighting fish) care guide

Betta and Siamese fighting fish: same animal

If you've searched both terms and landed here confused, don't be. Betta and Siamese fighting fish refer to the same species: Betta splendens, native to Thailand (formerly Siam) and surrounding Southeast Asia. The "betta" name comes from the genus; the "Siamese fighting fish" name comes from their history of being bred for staged fights. In the aquarium hobby today, you'll see both terms used interchangeably depending on where you shop or which forum you read.

What you will find in pet stores are almost exclusively captive-bred strains - veiltail, halfmoon, crowntail, plakat, and others - selected for exaggerated finnage and color. Wild Betta splendens look quite different: shorter fins, duller coloration. The care requirements are broadly the same across varieties, though the heavily finned show types need even gentler water movement than the shorter-finned plakat form.

Tank size: why bowls kill bettas

The pet trade has done bettas a serious disservice by marketing tiny cups and decorative vases as suitable homes. They are not. Bettas are labyrinth fish - they breathe atmospheric air directly at the surface - but that doesn't mean water quality is irrelevant. It means they can survive briefly in oxygen-poor water, not that they thrive in filth.

A small, unfiltered container accumulates ammonia rapidly. Ammonia burns gill tissue, damages fins, and suppresses immune function. Bettas in bowls don't live long, healthy lives; they survive for a while and then deteriorate. You'll see clamped fins, lethargy, and recurring infections.

5 gallons is the realistic minimum for a single betta. At that volume, a small filter and heater can maintain stable conditions with regular maintenance. 10 gallons is better - water parameters fluctuate less between water changes, there's room for décor and hiding spots, and if you want to add tank mates, you have space to work with. Anything under 5 gallons makes your job harder and your betta's life worse.

Water temperature and heating

Bettas are tropical fish from warm, shallow waters. Their optimal range is 76-82 °F (24-28 °C), with 78-80 °F (25-27 °C) being the sweet spot most experienced keepers aim for. Below 72 °F (22 °C), their immune system starts to suffer and they become susceptible to ich and other infections. Below 65 °F (18 °C), a betta will likely die.

If you live somewhere where room temperature reliably stays in the mid-70s Fahrenheit year-round, you might get away without a heater in summer - but in practice, most homes drop at night, in winter, or when air conditioning runs hard. A small adjustable heater (25W is usually sufficient for a 5-10 gallon tank) costs very little and removes the guesswork entirely.

Filtration and flow rate

Bettas need filtered water, but they don't need - and actively dislike - strong current. In the wild, they live in rice paddies, ponds, and slow-moving streams. A powerful filter output that pushes them around the tank causes chronic stress, fin damage from fighting the flow, and exhaustion.

What works well:

• Sponge filters driven by a small air pump - gentle, cheap, and easy to maintain.
• Small internal filters with the outlet aimed at the glass wall to diffuse flow.
• HOB (hang-on-back) filters with a DIY baffle - a piece of filter sponge or plastic bottle fitted over the outlet reduces the jet significantly.

The goal is biological filtration (beneficial bacteria converting ammonia to nitrite to nitrate) without creating a whirlpool. If your betta is hiding behind décor and avoiding half the tank, the flow is probably too strong. Understanding the nitrogen cycle will help you see why a cycled filter matters far more than the filter's brand or price.

Cycling your tank before adding fish

Most people who lose their first betta in the first few weeks didn't do anything dramatically wrong with feeding or temperature - they put a fish into an uncycled tank. An uncycled tank has no established colony of beneficial bacteria, so ammonia from fish waste has nowhere to go. It builds up and poisons the fish.

Cycle your tank before buying any fish. The process takes 4-6 weeks using a fishless method - adding ammonia and testing regularly until your filter bacteria are established. It's not complicated, but it does require patience. The full process is covered in our guide on how to cycle a fish tank.

Tank mates: what actually works

The question "can my betta live with other fish?" gets asked constantly, and the honest answer is: it depends on your individual betta. Some bettas are relaxed community fish. Others will shred anything they can catch. You won't know which you have until you try, so have a backup plan ready (a spare tank or divider) before adding tank mates.

Never do this

• Two male bettas together. They will fight until one (or both) is dead or severely injured. There is no exception to this rule.
• Fin-nipping species. Tiger barbs, serpae tetras, and some danio varieties will attack long-finned bettas. The damage happens fast and creates infection entry points.
• Fish that look like bettas. Brightly colored, long-finned males of other species - fancy guppies in particular - often trigger aggression. Your betta may see them as rivals.

What can work in a 10+ gallon tank

• Small, peaceful schooling fish: harlequin rasboras (Trigonostigma heteromorpha), ember tetras (Hyphessobrycon amandae), neon tetras (Paracheirodon innesi) - though neons' blue-red coloration occasionally triggers aggression in some bettas.
• Bottom dwellers: corydoras catfish, otocinclus - they occupy different tank levels and tend to be ignored.
• Snails: nerite and mystery snails usually work. Some bettas harass them; most don't.
• Shrimp: genuinely hit or miss. Amano shrimp are large enough to survive in many cases; cherry shrimp are more likely to become expensive snacks.

Always introduce tank mates with enough hiding spots and plants that the betta can't patrol every inch of the tank. If you're planning a community setup, our free stocking calculator can help you think through the numbers.

Female betta sororities

You'll read about keeping 4-6 female bettas together in a "sorority" tank. It can work, but it's not beginner territory. You need a tank of at least 20 gallons with heavy planting, you'll spend the first few weeks monitoring for hierarchy fights, and some combinations simply never settle. Don't attempt this in your first betta tank.

Décor, plants, and tank setup

Bettas need cover. In the wild they hide among vegetation and surface debris. A bare tank with nowhere to retreat is stressful, and a stressed betta develops health problems. Add:

• Broad-leaved plants near the surface - live or silk. Bettas rest on these. The classic "betta leaf hammock" accessory mimics this and genuinely gets used.
• Hiding spots: caves, driftwood, dense planting in corners.
• A lid. Bettas jump. Not occasionally - regularly. A gap in your lid is a gap your betta will eventually find at 2am.

Avoid sharp plastic decorations. Bettas have delicate fins that snag and tear. Do the "pantyhose test": run a piece of nylon stocking over any decoration. If it snags, the decoration will damage your betta's fins.

Feeding

Bettas are carnivores. Their mouths point upward and they're adapted to hunt insects and small invertebrates at the water surface. A diet based entirely on generic tropical flake food isn't appropriate - the protein content is usually too low and the plant-heavy filler doesn't suit their digestive system well.

Feed a good-quality betta-specific pellet as the staple - look for one with fish or shrimp listed as the first ingredient, not wheat or soy. Supplement with frozen or live foods: bloodworms, daphnia, and brine shrimp are all accepted readily and improve conditioning and coloration.

Feed once or twice daily, only what your betta eats in 2-3 minutes. Overfeeding is one of the leading causes of poor water quality in small tanks. Most experienced keepers fast their betta one day per week to prevent bloat and constipation.

Water changes and parameters

In a cycled, filtered 10-gallon tank, a weekly water change of 20-30% is usually enough to keep nitrates in check. In a 5-gallon tank, you may need to change water twice a week because waste accumulates faster relative to volume. If you're skipping water changes for weeks at a time, your betta is living in deteriorating conditions even if the water looks clear.

Target parameters for bettas:

• Ammonia: 0 ppm
• Nitrite: 0 ppm
• Nitrate: under 20 ppm (ideally under 10 ppm)
• pH: 6.5-7.5 - bettas are adaptable, but stable is more important than hitting a specific number
• Hardness: soft to moderately hard; they're not demanding here

For a full breakdown of what each parameter means and how to test, see our guide to aquarium water parameters, and for how often maintenance needs to happen, how often to do water changes covers it in detail. App-aquatic lets you log test results over time so you can spot trends before they become problems.

Common health problems and what causes them

Most betta health problems trace back to water quality or temperature, not bad luck.

• Fin rot: Ragged, receding fin edges. Caused by poor water quality and bacteria entering small tears. Fix the water first before reaching for medication.
• Ich (white spot): Fine white spots like salt grains across the body and fins. Usually triggered by temperature drops or stress. Raise temperature to 82-86 °F (28-30 °C) gradually and treat with an ich-specific medication.
• Velvet: Gold or rust-colored dust on the body, often first visible with a flashlight. More aggressive than ich - treat promptly with a copper-based medication.
• Swim bladder issues: Floating at the top or sinking to the bottom. Often diet-related (overfeeding, constipation). Fast for 24-48 hours; if it doesn't resolve, investigate further.

Is a betta right for you?

Bettas are often sold as low-effort starter fish, and that's misleading. They're not difficult to keep, but they do need a properly set up, heated, filtered tank and regular maintenance. What makes them genuinely good for beginners is that they're hardy enough to handle the occasional mistake, they're interactive and visually striking, and a single betta in a well-planted 10-gallon tank is a satisfying, manageable project. If you're looking at other options too, our guide to the best fish for beginners covers a range of species worth considering.

Get the tank cycled and stable before you buy the fish. Buy from a store where the bettas look