Betta Fish Care Guide — Tank, Water & Health
The Betta (Siamese fighting fish) is one of the most popular aquarium fish in the world — and one of the most misunderstood. This guide covers the correct tank, water, feeding and disease care to keep your Betta vibrant for years.
Understanding the Betta
Native to the shallow rice paddies, streams and floodplains of Thailand, Cambodia and neighbouring countries, the Betta splendens evolved a labyrinth organ that lets it gulp air from the surface. This is why Bettas survive in low-oxygen water — but it does not mean they thrive in a tiny bowl. In the wild they patrol territories several times larger than a typical cup, and a cramped, cold, dirty container is the fastest way to a short, stressed life.
Give a Betta warm, clean, gently filtered water and it rewards you with intense colour, flowing fins and genuine personality — many learn to recognise their keeper and beg at feeding time. The three pillars of Betta care are stable warmth, clean water, and a varied protein diet. Get those right and most problems never appear.
Tank Setup Step by Step
Follow these five steps before your Betta ever touches the water.
Choose a Tank of at Least 10 Litres
The "betta in a cup" myth kills more fish than any disease. A single Betta needs a minimum of 10 litres, and 20 litres makes water quality far more stable. More volume means slower parameter swings and a calmer, more colourful fish.
Add a Heater and Thermometer
Bettas are tropical fish from Southeast Asia and need water held at 25–28 °C. A small adjustable heater (25–50 W) plus a thermometer prevents the temperature crashes that cause lethargy, clamped fins and disease.
Install a Gentle Filter
A sponge filter or an adjustable hang-on-back filter turned to low flow keeps ammonia and nitrite at zero without blasting your Betta around. Their long fins tire easily in strong current, so aim the outflow at the glass to diffuse it.
Cycle the Tank Before Adding Fish
Run the tank for 2–4 weeks to grow beneficial bacteria that convert toxic ammonia into nitrate. Never add a Betta to a brand-new, uncycled tank — read our nitrogen cycle guide first to avoid the most common beginner killer.
Decorate With Soft Plants and Hides
Silk or live plants (java fern, anubias) and a cave give a Betta security and a resting spot near the surface. Avoid hard plastic plants with sharp edges — they tear delicate fins and open the door to fin rot.
Feeding Your Betta
Bettas are carnivores. A protein-rich staple plus rotated treats keeps colour bright and prevents bloat. Feed only what your Betta eats in two minutes — overfeeding is the number-one cause of illness.
| Food | Role | Frequency |
|---|---|---|
| Betta pellets | Staple — high-protein floating pellet | Daily, 2–4 pellets |
| Frozen bloodworms | Treat — rich protein, great colour boost | 2–3× per week |
| Brine shrimp | Treat — encourages natural hunting | 1–2× per week |
| Daphnia | Fibre — natural laxative, prevents bloat | As needed for constipation |
Common Betta Diseases
Catch these early — almost every Betta illness traces back to cold or dirty water.
Fin Rot
Signs: Ragged, receding or blackening fin edges
Cause: Poor water quality, injury
Fix: Water changes, clean parameters, aquarium salt or antibacterial treatment
Ich (White Spot)
Signs: Grains of "salt" on body and fins, flicking
Cause: Parasite, temperature stress
Fix: Raise temperature to 28–30 °C gradually, ich medication
Swim Bladder / Bloat
Signs: Floating sideways, sinking, swollen belly
Cause: Overfeeding, constipation
Fix: Fast 2–3 days, then feed daphnia; smaller portions
Velvet
Signs: Gold/rust dusting, clamped fins, lethargy
Cause: Parasite, low immunity
Fix: Dim lights, raise temperature, copper or velvet-specific treatment
Frequently Asked Questions
Do Betta fish really need a heater?
Yes. Bettas are tropical fish and become sluggish, stop eating and get sick below about 24 °C. Unless your room stays reliably at 25–28 °C year-round, a small heater is essential — it is the single most impactful upgrade for a Betta kept in a cool climate.
Can two Betta fish live together?
Two males will fight, often to the death — that is why they are called Siamese fighting fish. A male and female should only share space temporarily for supervised breeding. If you want multiple Bettas, keep them in separate tanks or use a divided tank.
How often should I change the water?
In a filtered, cycled 20 L tank, change 20–25% of the water weekly and gently vacuum the substrate. In a smaller tank you will need to change water more often. Always match temperature and dechlorinate tap water before adding it.
Why is my Betta not eating?
Common causes are water too cold, poor water quality, stress from a recent move, or overfeeding the day before. Check the temperature and test your water first. A healthy Betta at the right temperature will usually eat eagerly within a few days of settling in.
What tank mates work with a Betta?
In a 20 L or larger tank, peaceful bottom dwellers like a small snail or a few Corydoras can work, but success depends on the individual Betta’s temperament. Avoid fin-nippers and other colourful, long-finned fish. Many Bettas are happiest alone.
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