The core supplies you need for a betta fish tank are a tank of at least 5 gallons, a gentle low-flow filter, a reliable heater, a thermometer, a water conditioner, and a test kit. That's the honest minimum. Bettas kept in smaller containers without filtration or heating can survive but rarely thrive, and the water quality problems that come from inadequate setup are the leading cause of disease and early death in captive bettas.
Getting the setup right from the start is much easier than troubleshooting water quality issues with a sick fish. This guide covers each supply category with specific product recommendations, explains why bettas need different conditions than many other fish, and gives you a clear list of what to buy for different budget levels.
The Tank: Why Size and Shape Matter for Bettas
Bettas need a minimum of 5 gallons. This isn't arbitrary; smaller volumes fluctuate in temperature and water quality so rapidly that they require daily water changes to stay safe, which most owners don't maintain. A 5 gallon tank with a filter and heater is stable and requires only a 25-30% water change per week.
Tank shape also matters. Bettas breathe air from the surface using their labyrinth organ, so they need easy access to the water surface. Tall, narrow tanks with more than 12" of depth make surface access harder. Long, shallow tanks (like a 10 gallon standard or a 5.5 gallon standard) are better suited than the vertical cylinder or half-moon aquariums sometimes marketed specifically to betta owners.
Good tank options for bettas:
Fluval Spec V (5 gallon): A popular choice with an integrated filtration system and good lighting for low-light plants. The filter output is adjustable, which is important for bettas (more on that shortly). Around $80-90.
MarineLand Portrait 5-gallon: Similar to the Spec V with a different aesthetic. Curved glass front panel, built-in back filter. About $45-55.
Standard 10-gallon aquarium: A plain 10-gallon tank from brands like Aqueon or Marineland costs $15-25 at pet stores. You'll add a separate filter and heater, but the total setup cost is competitive and you get more space.
Filtration: Why Flow Rate Matters for Bettas
Bettas evolved in slow-moving or still water. Their long, flowing fins aren't built for current. A filter that produces even moderate flow can exhaust a betta, cause fin damage from being pushed against hard surfaces, and produce chronic stress that suppresses the immune system.
This doesn't mean no filtration. It means choosing a filter with adjustable or inherently low flow, or modifying a basic filter to reduce output.
Sponge filters are the gold standard for betta tanks. They run off an air pump, produce gentle biological filtration, and create minimal water movement. The Hikari bacto-surge sponge filter and the Aquarium Technology Inc (ATI) sponge filters are both reliable. A basic sponge filter with an Aquatop AP-10 air pump costs about $15-20 total and is extremely effective in a 5-10 gallon betta setup.
Hang-on-back filters with baffling: If you prefer a HOB filter, the AquaClear 20 or AquaClear 30 can be flow-restricted using the included adjustable intake and by placing a sponge or mesh bag over the outlet to diffuse the return flow. A water bottle cap trick (placing a small plastic bottle over the filter outlet) is a popular DIY baffle that many betta keepers use.
Fluval Spec V's integrated filter: Acceptable stock, but benefits from a small sponge placed over the intake and a piece of foam tucked into the outlet to reduce flow. Many Spec V owners do this modification immediately after purchase.
Heating: The Most Underrated Supply
Bettas are tropical fish that need water temperature consistently between 76-82°F. Most homes don't reach this temperature reliably, especially at night in winter. A heater is not optional.
For a 5-gallon tank, a 25-50W heater is appropriate. For a 10-gallon, 50W is right.
Aqueon Pro 50W: One of the most reliable small heaters on the market. Shatterproof plastic body, accurate thermostat, and fully submersible. Around $20-25. I've seen these run accurately for years without drift.
Eheim Jager 50W: The other frequently recommended choice. German-made, accurate, adjustable thermostat with a recalibration slot. Slightly more expensive at $25-35 but has an outstanding track record.
Inkbird ITC-306T with cheap heater: For hobbyists who want precise temperature control, an Inkbird temperature controller ($25-35) running a basic $15 heater is more accurate than most standalone heaters. The Inkbird reads a probe and switches the heater on and off to maintain within 0.1°F of setpoint.
Avoid the strip heaters and flat panel heaters sometimes sold for nano tanks. These are unreliable and frequently malfunction.
Water Conditioning and Testing
Seachem Prime: The single most important water conditioner you can buy. It neutralizes chlorine, chloramine, and heavy metals in tap water, and temporarily detoxifies ammonia and nitrite in a crisis. Dosing is 1ml per 50 gallons, so a 100ml bottle lasts an extremely long time in a 5-gallon betta tank. Around $5-8.
API Freshwater Master Test Kit: This liquid-based kit tests pH, ammonia, nitrite, and nitrate, the four parameters that matter most for betta health. At $25-30, it's more expensive than strip tests but far more accurate. Strip tests frequently give false safe readings for ammonia and nitrite.
API 5-in-1 strips: Adequate for quick weekly checks once your tank is cycled and you know what the normal parameters look like. Not reliable for diagnosing actual problems.
The single most important thing you can do for your betta is cycle the tank before adding fish. Cycling establishes beneficial bacteria that convert ammonia (from fish waste) to nitrite, then to the less harmful nitrate. A properly cycled tank maintains zero ammonia and zero nitrite continuously. The API Master Test Kit lets you confirm this.
Plants, Decor, and Substrate
Bettas do well with live plants, and the benefits are real: plants consume nitrate, provide cover that reduces stress, and create a more natural environment. Easy beginner plants that work in a betta tank include java fern, anubias, and java moss, none of which need strong lighting or CO2 injection.
For substrate, plain gravel or dark sand both work. Avoid sharp-edged gravel that can tear fins. Bettas that rest on the substrate (they do this regularly) benefit from smooth, soft substrate.
Decorations should have no sharp edges. Run a pantyhose or nylon over any plastic decoration before adding it; if it snags, it will tear fins.
Silk plants are a safer choice than hard plastic plants. Live plants are better than both.
A small piece of driftwood or a few smooth river rocks add cover and make the tank more interesting for the fish. Bettas explore their territory actively and benefit from environmental complexity.
For full equipment recommendations across different types of aquariums including betta setups, check out our best aquarium equipment and top aquarium equipment guides.
Budget Breakdown
Minimum effective setup (5 gallons): - 5.5 gallon standard tank: $15-20 - Sponge filter + air pump: $15-20 - Aqueon Pro 25W heater: $15-18 - Thermometer (stick-on or digital): $5-8 - Seachem Prime: $6-8 - API Master Test Kit: $25-30 - Basic substrate: $5-10 - Total: approximately $86-114
Better setup with more comfort features: - Fluval Spec V: $80-90 - Aqueon Pro 50W: $20-25 - API Master Test Kit: $25-30 - Seachem Prime: $6-8 - Live plants (java fern, anubias): $10-15 - Total: approximately $141-168
FAQ
Can a betta fish live in a 1-gallon tank? Physically yes, but not well. Small volumes can't support a cycled filter, temperatures fluctuate dangerously, and ammonia spikes require daily partial water changes to prevent poisoning. A 5-gallon minimum is the standard recommendation because it's the smallest size that supports stable water chemistry with normal maintenance.
Do bettas need a filter? Yes. The nitrogen cycle requires a filter with biological media to house the beneficial bacteria that process ammonia. Without filtration, ammonia accumulates rapidly and causes gill damage, immune suppression, and organ failure. The filter doesn't need to be powerful, just functional.
What temperature should betta tank water be? 76-82°F is the standard range. The sweet spot for most bettas is 78-80°F. Below 74°F bettas become lethargic and vulnerable to disease. Below 68°F is life-threatening.
How often should I change the water in a betta tank? In a properly cycled 5-10 gallon tank with a filter, a 25-30% water change once per week maintains excellent water quality. Uncycled tanks or tanks with heavy plant load need changes assessed by testing rather than a fixed schedule.