Start with a tank that is at least 5 gallons

A betta fish needs a minimum of 5 gallons to thrive, though 10 gallons or larger is better. Many people keep bettas in 1-gallon bowls or small tanks, but this causes stress, poor water quality, and shortened lifespans. A 5-gallon tank gives your betta room to swim, explore, and exhibit natural behaviors like building bubble nests.

The tank shape matters too. Long, horizontal tanks are better than tall, narrow ones because bettas swim side-to-side more than up-and-down. A standard 10-gallon aquarium (20 inches long, 10 inches wide, 12 inches tall) is ideal for a beginner and costs $20 to $40 new. Used tanks are often cheaper and work just as well.

Key Takeaways

  • Bettas require at least 5 gallons of water, a heater to keep temperature between 76 and 80 degrees Fahrenheit, and a gentle filter to maintain water quality.
  • Add a substrate (gravel or sand), live or silk plants for hiding, and decorations with no sharp edges that could tear the betta's delicate fins.
  • Let the tank run for 5 to 7 days before adding your betta so beneficial bacteria can establish and the water chemistry stabilizes.
  • Test water weekly for ammonia, nitrite, and nitrate using a liquid test kit, and do a 25 percent water change every week to keep the tank clean.
  • Keep the tank away from direct sunlight, drafts, and loud noises, and maintain a consistent day-night cycle with 8 to 12 hours of light per day.

Install a heater and filter before adding water

Bettas are tropical fish and need warm water. A submersible aquarium heater keeps the temperature between 76 and 80 degrees Fahrenheit—the range where bettas are most active and healthy. A 50-watt heater works for 5- to 10-gallon tanks. Place it on the back wall, away from decorations, so water flows around it evenly. Plug it in only after the tank is filled.

A gentle filter removes waste and keeps ammonia and nitrite from building up. Bettas have long, flowing fins and dislike strong currents, so avoid high-powered filters. A sponge filter (powered by an air pump) or a small hang-on-back filter set to low flow works well. If the current pushes your betta around the tank, reduce the flow or add plants to break up the water movement.

Add substrate, plants, and hiding spots

Cover the tank bottom with 1 to 2 inches of substrate—either aquarium gravel or sand. Substrate gives beneficial bacteria a place to live, anchors plants, and looks more natural than a bare bottom. Rinse gravel under running water before adding it to remove dust. Avoid colored gravel dyes, which can leach into the water.

Bettas need places to hide and rest. Add live plants like Java fern, Anubias, or Marimo moss balls, which also absorb nitrate and improve water quality. If live plants seem difficult, use silk plants instead—plastic plants can tear a betta's fins. Include a cave or hollow decoration where your betta can retreat. Check all decorations for sharp edges by running a pantyhose over them; if it snags, sand it smooth or remove it.

Cycle the tank for 5 to 7 days before introducing your betta

Before your betta arrives, run the heater, filter, and lights for at least 5 to 7 days. This allows beneficial bacteria to colonize the substrate and filter media, which breaks down fish waste into less toxic compounds. During this time, the water will also reach the correct temperature and any chlorine from tap water will evaporate.

You can speed up cycling by adding a small pinch of fish food every other day—the decaying food releases ammonia, which feeds the bacteria. On day 5 or 6, test the water with a liquid aquarium test kit (not strips, which are less accurate). You are looking for ammonia and nitrite readings of 0 ppm and nitrate below 20 ppm. If ammonia or nitrite are still high, wait another 2 to 3 days before adding your betta.

Fill the tank and check water parameters

Use dechlorinated water—either bottled aquarium water or tap water treated with a dechlorinator product. Fill the tank slowly, pouring water onto a plate or into your hand so it does not disturb the substrate and plants. Leave about 1 inch of space at the top to prevent splashing when the filter runs.

Test the water one more time before adding your betta. Ammonia should be 0 ppm, nitrite should be 0 ppm, and nitrate should be below 20 ppm. The pH should be between 6.5 and 7.5 (most tap water falls in this range). Temperature should be steady at 76 to 80 degrees Fahrenheit. If any reading is off, wait another day and retest.

Acclimate your betta to the new tank

When your betta arrives, do not drop it directly into the tank. Acclimation lets the fish adjust to the new water temperature and chemistry gradually, reducing stress and shock. Float the sealed bag your betta came in on the tank surface for 15 to 20 minutes so the water inside the bag reaches the same temperature as the tank.

After 15 minutes, open the bag and slowly add small amounts of tank water to the bag—about a quarter cup every 5 minutes—for 20 to 30 minutes total. This mixes the bag water with tank water gradually. Then gently pour the betta into the tank, leaving the bag water behind. Turn off the lights for a few hours so your betta can settle without stress.

Maintain the tank with weekly water changes and testing

Every week, test ammonia, nitrite, and nitrate with your liquid test kit. Ammonia and nitrite should stay at 0 ppm; if they rise above 0.5 ppm, do a 25 percent water change when ready. Nitrate will gradually increase and should be kept below 40 ppm with weekly 25 percent water changes.

To do a water change, remove 25 percent of the water using a siphon or cup, then refill with dechlorinated water at the same temperature as the tank. Never remove the betta or decorations unless you are cleaning them. Avoid changing more than 50 percent of the water at once, which can crash the beneficial bacteria colony and cause ammonia spikes.

Position the tank in a stable location away from hazards

Place the tank on a sturdy stand or table that can support its weight—a 10-gallon tank filled with water weighs about 90 pounds. Keep it away from direct sunlight, which causes algae blooms and temperature swings. Avoid placing it near heating vents, air conditioners, or drafty windows, which make temperature control difficult.

Keep the tank away from loud noises, vibrations, and sudden movements. Bettas are sensitive to stress, and a tank near a speaker, television, or high-traffic area can cause the fish to hide constantly or stop eating. A quiet corner of a bedroom or living room is ideal. Maintain a consistent day-night cycle by using an aquarium light on a timer for 8 to 12 hours per day.

Frequently Asked Questions

Can I use tap water straight from the faucet?

Tap water contains chlorine and chloramine, which harm fish. You must treat it with a dechlorinator product before adding it to the tank. Dechlorinator is inexpensive (about $5 to $10 per bottle) and removes these chemicals in seconds. Some people let tap water sit uncovered for 24 hours, but this only removes chlorine, not chloramine, so a dechlorinator is more reliable.

Do I need a filter if I do frequent water changes?

A filter is strongly recommended because it removes waste continuously and keeps ammonia and nitrite from spiking between water changes. Without a filter, you would need to do 50 percent water changes every 2 to 3 days, which stresses the betta and is impractical. A gentle sponge or hang-on-back filter makes maintenance much easier.

What temperature should the water be?

Bettas thrive between 76 and 80 degrees Fahrenheit. Below 74 degrees, they become sluggish and stop eating. Above 82 degrees, they become stressed and prone to disease. A submersible heater with a thermostat maintains the correct temperature automatically and costs $15 to $30.

How often should I clean the tank?

Do not do a full tank cleaning. Instead, do a 25 percent water change every week and rinse the filter media in old tank water (never tap water) every 2 to 4 weeks. A full cleaning removes beneficial bacteria and causes ammonia spikes. Only remove decorations if algae builds up or they become visibly dirty.

Can I keep plants in the tank if I do not have a light?

Low-light plants like Java fern and Anubias survive with minimal light, but they grow slowly. An aquarium light on a timer for 8 to 12 hours per day helps plants grow and gives your betta a natural day-night cycle. A basic LED light costs $20 to $40 and uses very little electricity.