The short answer
Routinely, the betta can stay in: aquatic vet Dr. Jessie Sanders’s general cleaning page says of fish “just keep an eye on them and don’t suck them up!” Unplug all; give the heater its maker’s wait (30 minutes on Hydor’s support page). Siphon, never all the water; refill slowly with treated, temperature-matched water; prime the filter; plug in once full.
This guide is for one betta in a freshwater tank, glass or acrylic, filtered or a small unfiltered container. For tank sizes, see our guide to how big a tank a betta needs.
Betta cleaning schedules: filtered tank or small unfiltered container
Water change percentage and frequency by source; they differ.
| Source (type) | Filtered tank | Small unfiltered container |
|---|---|---|
| Aqueon betta care guide (aquarium maker) | 10% every week or 25% every 2 weeks; change the filter cartridge at least monthly | 1/3 of the water every 3 to 4 days (its general page: avoid over 25%) |
| PetMD betta care sheet (vet-written; PetMD by Chewy) | Weekly: test, siphon, change 15–25%; monthly: algae “as needed”, replace filter media “as appropriate” | Not given |
| Tree of Life (exotic-pet vet clinic) | 25–50% weekly | Not given |
| Dr. Sanders’s betta page (aquatic vet) | Filter cleaned at least every 2 weeks | “No fish should live in a bowl.” |
The Spruce Pets, a pet-care publisher, in a tank roundup bylined to Dr. Sanders, on a 2.6-gallon kit: “Keep in mind that a nanosystem will require more cleaning and maintenance due to the low water volume. If you do not have time for weekly or twice-a-week maintenance, get a larger system.”
Before you start: tools and hands
- Cleaning tools. A siphon gravel vacuum, a bucket, an algae pad that suits your tank (step 4), a thermometer, water conditioner and a test kit. PetSmart, a pet retailer, says to “Use an appropriately sized gravel vacuum for your aquarium.” Aqueon: “Don’t use buckets, scrub pads or any other equipment on your aquarium that have been used with soap or other chemicals.”
- Clean hands. Dr. Sanders starts with “Wash your hands and arms to your elbows.” PetSmart: “You’ll want to remove all lotions and soaps from your hands before you do.”
- Gloves. The CDC, a US federal health agency: “Wear gloves when cleaning or caring for your aquarium, especially if you have cuts or wounds on your hands or if you plan to work with rough rocks or spiny fish.” Also: “People with weakened immune systems should let others in the household care for the fish tank when possible. If this isn’t possible, they should wear gloves.” and “Don’t let children younger than 5 years old clean or handle aquarium items.”
Seachem Prime is compared in our water conditioner roundup; the API master kit is in our freshwater test kit roundup.
| # | Preview | Product | Price | Link |
|---|---|---|---|---|
| 1 |  | Seachem Prime -500 ml/ 17 fl. oz. | Chemical Remover and…Conditioner for the refill | $16.62 Prime | Check on Amazon |
| 2 |  | API Freshwater Master Test Kit 800-Test Freshwater Aquarium…Test kit for step 2 | Check on Amazon |
Cleaning around your betta, step by step
Unplug everything in the tank, then wait for the heater
Fluval’s AquaClear filter manual: “Always unplug or disconnect all appliances in the aquarium from electricity supply before placing hands in water, before putting on or taking off parts and while the equipment is being installed, maintained or handled.” Dr. Sanders: “Unplug filter and lights.” and “If you have any UV lights, unplug those too.” Hydor, a heater maker, gives two waits. Its Theo manual: “To avoid possible breakages due to thermal shock, the heater should be disconnected from the power supply at least 5 minutes before taking it out of the water or before adding or changing the water.” Its support page: “When undertaking water changes Hydor recommend that the heater is turned off and unplugged from the power socket at least 30 minutes before any waterchange.” Fluval’s E heater manual: “If it has to be taken out of the water or when transferring or changing the water, disconnect the heater from the power source and wait for at least 30 minutes to allow it to cool down.” Wait before any water comes out. Our reading, where a maker’s pages differ (as Hydor’s do) or you have no manual: the longest planned time quoted here, 30 minutes; otherwise, your heater manual’s time. Fluval’s 1 hour is for a heater that came out of the water while on: “If the heater is accidentally removed from water while operating, DO NOT re-submerse it in water. Unplug it and let it cool down for at least 1 hour before reusing.” Put on gloves (CDC, above, which also says who should not do this job).
Test the water while the heater cools
Everything stays unplugged until step 10. PetMD: “Test tank water weekly and focus on key parameters like ammonia, nitrite, nitrate, and pH.” Our guides to lowering ammonia and nitrites cover high readings.
Ready the new water
Everything stays unplugged until step 10. Aqueon’s betta guide: “Always treat tap water with Aqueon BettaBowl Plus or Water Conditioner before adding it to the aquarium.” Aqueon’s do’s and don’ts: “Replacement water should be the same temperature as the aquarium water”. Check the bucket against the tank with the thermometer. Our water change guide covers faucet changers. Dose by the label.
Wipe algae off the glass, only as needed
Everything stays unplugged until step 10. PetMD’s monthly list: “Clean algae from glass/decor as needed”. Dr. Sanders: “It is critical that you use a scrubber that is appropriate for your tank type. Glass scrubs are more abrasive and can scratch acrylic, causing a hazy appearance.” The Spruce Pets: “you should never use harsh chemicals or detergents, which can leave behind residue, to clean the tanks.” Some algae is fine; Dr. Sanders says “Algae is a sign that your tank is healthy.”
Scrub only decor that is dirty
Everything stays unplugged until step 10. Our reading of PetMD is to leave the rest: “Avoid “deep cleaning” that strips everything at once—your tank’s beneficial bacteria live on surfaces like filter media and decor.” When Dr. Sanders scrubs synthetic decor, it is at the sink “with hot water and a designated toothbrush”: “Do NOT use any detergent!”
Siphon the gravel around your betta
Everything stays unplugged until step 10. Aquarium Co-Op, an aquarium retailer, notes that “Aquarium siphons use gravity”, so the bucket sits below the tank (our reading). Dr. Sanders’s tank-cleaning page (all fish, not betta-specific): “Press the end of the siphon into the substrate, allow the gravel or sand to move 1/4 to 1/3 of the way up the tube, then pull the siphon up, breaking the siphon.” Co-Op: “There is no need to remove the fish while using the aquarium siphon, since the process of catching them is more stressful than slowly vacuuming around them.” PetSmart: “Watch for any fish, shrimp, or snails who may be caught in the suction.” More on technique: our gravel cleaning guide and, for sand, cleaning aquarium sand.
Stop at your amount from the table, then check the bucket
Everything stays unplugged until step 10. Aqueon’s betta guide: “Never change all of your betta’s water at one time!” Dr. Sanders: “Do not remove more than 50% of the tank water at a time to avoid sudden swings in temperature and pH.” Aqueon’s do’s and don’ts, a general page, sets a lower cap: “Avoid water changes of more than 25% as larger water changes can stress your fish and upset the balance in your aquarium.” Its betta guide’s 1/3 for unfiltered containers is higher; the caps differ. Dr. Sanders, on the bucket: “When it gets within 3″ of the top, pull the siphon all the way out.” One owner on r/bettafish, a Reddit forum, found that their betta “somehow ended up in the bucket”; a reply there says to “check the bucket before dumping it”. The CDC: “Dump tank water and clean aquarium items in a bathtub, laundry sink, or outside instead of a kitchen sink when possible.” and “Clean and disinfect sinks and bathtubs after using them to dump aquarium water or clean aquarium items.”
Rinse filter media in the old water, or save the filter for another day
Everything stays unplugged until step 10. Dr. Sanders: “Remove filter media and rinse gently or squeeze in collected bucket of waste water. Do NOT use tap water. The chlorine in tap water that makes it safe for us to drink kills your good bacteria.” On timing, she cleans media in the same session; PetSmart says “Filter cleaning should be done approximately once per month, but not during the gravel cleaning as too much beneficial bacteria can be lost at once.” Aqueon’s do’s and don’ts: “Change filter cartridges at least once a month. Check them weekly and rinse as needed.” Dr. Sanders differs: “You do NOT have to replace your filter media every month (we know it says so on the box, please disregard!)”. Check your filter’s manual and our filter cleaning guide.
Refill slowly and set the decor back
Everything stays unplugged until step 10. Dr. Sanders pours slowly or uses a smaller vessel “to avoid a heavy current in your tank that may hurt your fish.” The Spruce Pets: “Avoid putting any decorations with sharp or pointy edges, including plants that can tear up delicate betta fish fins.”
Prime the filter, plug everything back in, then close the lid
Fluval: “Do not allow filter pump to run dry.” Prime a power filter before you plug it in; your filter’s manual comes first. Dr. Sanders: “Prime your filtration by pouring some tank water into the filter base.” (hang-on-back filters; canister filters vary). After a filter clean, Fluval’s AquaClear manual: “Follow operating instructions to restart and prime power filter.” Then plug in the filter and other gear; for the heater, Hydor: “The Heater can ONLY then be turned back on when the Aquarium is full and the heater is completely submerged.” Its Theo manual: “Do not connect the heater to the power supply when it is not submerged in water.” With your hands out, close the lid; Aqueon: “bettas are jumpers, so keep a secure lid on the tank!” The CDC says to wash your hands “with soap and running water” after cleaning the tank. Dr. Sanders: “Pay close attention to your fish to ensure everyone is acting normal after the water change.”
The general routine for any tank is in our guide to cleaning a fish tank.
Bowls and small unfiltered containers
Aqueon’s betta guide says the betta’s labyrinth organ lets it breathe air at the surface, “making it possible for them to live in small aquariums without circulation”. For those, it gives the heavier schedule in the table: “In small unfiltered containers, change 1/3 of your betta’s water every 3 to 4 days”, using its siphon gravel cleaner. Steps 1-7, 9 and 10 still apply without the filter parts, including the heater wait if there is a heater.
Dr. Sanders’s betta page: “If your betta is in a bowl, please get them into a standard aquarium tank with filter.” To keep a filter’s flow gentle for a betta, see how to reduce filter current.
Betta tank don’ts
Each is also inside its step above.
- No detergent or harsh chemicals on glass or decor, and no bucket or pad used with soap (tools, steps 4-5).
- No glass scrub on an acrylic tank (step 4).
- No hands in the water with anything plugged in, and no water out before the heater’s wait (steps 1-9).
- No changing all the water at once (step 7).
- No tap water on filter media (step 8).
- No heater on before it is fully under water, and no filter run dry (step 10).
If your betta seems off afterward
Test the water and contact an aquatic veterinarian; we do not diagnose or treat fish. PetSmart points owners to the Find a Fish Vet “tool at fishvets.org or wavma.org”. Betta temperature ranges are in our guide to what temperature a fish tank should be.
Heater, filter and kit manuals come first
Where your heater’s, filter’s or tank kit’s own manual differs from the steps above, follow it. Fluval’s AquaClear manual adds: “Cleaning and user maintenance shall not be made by children without supervision.”
Ready to buy?
Our betta tank roundup compares eight kits by size, and our Tank Setup & Care section covers other routine maintenance tasks.
Frequently Asked Questions
Q. Should you remove a betta when cleaning the tank?
Not for routine cleaning, on the sources here, none of which is about bettas in particular. Dr. Sanders: “Your fish can stay in the tank during cleaning, just keep an eye on them and don’t suck them up!” PetSmart: “Do not remove fish for routine tank maintenance.”
Q. Where can a betta go while you clean?
The CDC suggests an option: “Consider purchasing a second aquarium to be used when you’re cleaning your first tank, or to house new fish before you place them in your established tank. Having a second tank to temporarily house fish may help reduce their stress and disease.” Co-Op and Dr. Sanders instead leave the fish in, and Co-Op calls catching it “more stressful”. None of the vet or maker sources here gives a method for moving a betta out.
Q. Do betta fish like clean or dirty water?
PetMD: “Even though bettas are small, they do best with stable, clean water, warm temperatures, and a setup that helps them feel secure”.
Q. How do you clean a betta tank with live plants?
PetSmart: “If you have live plants, trim any excessive growth or dying leaves.”
Sources (15)
- Aqueon, Betta Care Guide (maker)
- Aqueon, Do’s and Don’ts (maker)
- PetMD, Betta Fish Care Sheet (vet-written; PetMD by Chewy)
- Tree of Life, Betta Fish Care (vet clinic)
- Dr. Sanders, betta care (aquatic vet)
- Dr. Sanders, tank cleaning (aquatic vet)
- The Spruce Pets, betta tanks (publisher roundup; vet byline)
- PetSmart, maintenance guide (retailer)
- Aquarium Co-Op, aquarium siphon (retailer)
- Fluval, AquaClear manual (maker)
- Fluval, E heater manual (maker)
- Hydor, Theo manual (maker; distributor-hosted PDF linked from hydor.com/products/theo)
- Hydor, support page (maker)
- CDC, Fish (agency)
- r/bettafish thread (forum)
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