Wash your hands and gather a clean bucket, siphon or cup, algae scraper, and dechlorinated water
Turn off and unplug the filter, heater, and lights
Move the betta to a temporary container with tank water if a full cleaning is needed
Remove decorations, plants, and equipment
Siphon out 20–30% of the water for a partial water change
For a dirty tank, remove more water only if necessary and keep the fish safe
Rinse decorations and equipment with old tank water
Wipe algae from the glass with a clean sponge or scraper
Rinse filter media only in old tank water, not tap water
Clean the gravel lightly with a gravel vacuum during water removal
Refill the tank with dechlorinated water at the same temperature as the tank
Add water slowly to avoid disturbing the substrate and fish
Reinstall the filter, heater, and decorations
Turn equipment back on and check that everything is working
Return the betta to the tank if it was removed
Test water parameters regularly and clean on a weekly schedule