How often should you change a goldfish's water?
Sophia Koch
Updated on February 21, 2026
Generally speaking, you should change some of your goldfish's tank water once per week. We say “generally speaking”, because you will need to do more regular water changes in some situations.
How often should you clean goldfish water?
A goldfish bowl without a filter should be cleaned twice a week. With a filter you can clean it every 7-10 days.How often should you change the water in a goldfish bowl?
You should change the water in your fish bowl at least once per week, if not more often. Regular cleaning of a fish bowl serves two purposes. First, it will eliminate any odors coming from the bowl. Secondly, it will help keep your fish healthy.Can goldfish live in tap water?
Goldfish can only live in tap water when it has been properly treated to remove harmful chemicals. What is this? Tap water contains chemicals that will kill all of the 'good bacteria' in your tank. Good bacteria develops through a process called cycling, which we talk about in more detail here.How do you keep goldfish water clean?
Begin by scraping away excess algae from the tank sides with an algae scraper, and then vacuum up any waste or food scraps accumulating on the floor of the tank. Finally, siphon out 20 percent of the tank water and replace it with fresh water that has been treated to remove chemicals and chlorine.How Often to Change Goldfish Water?
Can change goldfish water everyday?
How much water should you change each time? You may have noticed that we said to change “some of” your goldfish's tank water each week. You should not change all of the water at once! In a properly cycled tank, we suggest a weekly water change of around a third of your goldfish tank's water.How do you change a goldfish's water?
The 6 Steps for Goldfish Nano and Small Tank Water Changes are:
- Shut it down. Turn off the heater, filter, and other tank electronics. ...
- Vacuum/siphon. Using the gravel vacuum, create suction. ...
- Prepare clean water. ...
- Toss the old water. ...
- Add clean water. ...
- Restart. ...
- Shut it down. ...
- Connect the tubing.
Do goldfish need fresh water?
If you really want to take the best care possible of your goldfish, then making sure they have the best water possible is paramount! After all, they need fresh, clean water as much as we need fresh, clean air.Why are my fish dying after water change?
Because the fish live in the water and the changes happen gradually, they adjust to it. When a sudden, large water change occurs, it causes such a drastic shift in the water parameters that the fish often cannot tolerate it and they die.Are goldfish sensitive to water changes?
Fortunately, goldfish are not nearly as sensitive to large water changes as other freshwater fish, and a large water change will not shock goldfish. The best tool any goldfish owner can have is a water changing hose that can be attached to the sink.How often should you change gravel in fish tank?
If you have a healthy and well-balanced fish tank, you may be able to go for several months without cleaning the gravel. However, even with a highly efficient tank, it is a good idea to clean gravel at least once every two to three months.Why is my goldfish water so cloudy?
If your goldfish tank is cloudy after a water change, it's most likely due to the fact adding water has kicked up all the silt and muck from the gravel. If this is the case, it should settle down after a few hours. If it's more than a couple of days, then it's probably a bacterial bloom.Why does my fish tank water get dirty so fast?
Use the Right Size Tank First, be sure your tank is the proper size for the fish you keep. If your tank is too small, the fish will be stressed and the tank will get dirty much faster. Your tank should not be overly large, however, or the fish will be uncomfortable and it will be much more space to keep clean.How often should I feed my goldfish?
Feed 2-3 times daily. It is important to avoid overfeeding goldfish as this can cause indigestion and/or contaminate the tank. In terms of the amount to feed, a good rule of thumb is to only feed an amount that the goldfish can consume in under two minutes or only feed as much as the size of the goldfish's eye.When should I change my fish tank water?
Recommended
- For a smaller tank, change out 10%-15% of the water each week.
- For a larger tank, change 20% of the water each week.
- If you use tap water, allow it to sit for three days.
- Use a dechlorinator before pouring fresh tap water into your tank.
- Test the water quality daily to ensure balanced pH levels.
Do goldfish need a filter?
Yes. Goldfish, as well as most fish, need a filter. It helps pump oxygen into the water and keeps the tank cleaner for longer.How do I change the water in my fish tank without killing the fish?
Dechlorinate the waterThat chlorine can also kill beneficial bacteria in our filters and harm fish, so we must always add a liquid dechlorinator (also known as tap safe,) every time we introduce new tapwater to our tanks.