How to Clean a Goldfish Aquarium

How to Clean a Goldfish Aquarium

It’s not usually recommended to completely clean out your entire goldfish aquarium but sometimes some serious spring cleaning needs to be done for proper goldfish care.

During this cleanings you might want to set up a temporary home for your goldfish to lessen the stress they might experience. Use some of the water from the tank you plan on cleaning and place it in your temporary goldfish tank. Next, use a plastic container to scoop up the fish. To avoid any injuries to your goldfish, only use a net if you have to.

Goldfish Aquarium

First unplug everything to avoid any potential electric shock

Goldfish Accessories

Remove all your goldfish accessories and rinse them off in a sink. Then fill the sink with hot water and allow all of your ornaments to soak. Allow them to soak for the entire time you are cleaning your goldfish aquarium. To be safe, don’t use any cleaning products or soap on your goldfish accessories.If you have any potted living aquatic plants, dig them up and move them to one side of your tank or place them in a temporary tank so they will be out of the way when you clean the aquarium glass, gravel and filters. Being careful not disturb any roots, scrub off any algae growth that might have accumulated on any drift wood or rocks that have aquatic plants attached to them.

Aquarium Glass

Using your algae scrubber, scrub down the sides and corners of your aquarium glass. You might need to use some elbow grease to get it off or a razor blade (use a plastic blade on acrylic tanks) to get the extra algae off. Some algae is beneficial; leaving a tiny bit behind will actually add to aquarium’s health.

Substrate Gravel

When all you have left is a gravel bottom, use an aquarium gravel cleaner to suck up all the dirt, waste and water into another bucket. Go slowly through the gravel moving the gravel cleaner over an inch every two seconds. If you don’t have a gravel cleaner, use your hands to mix up the gravel and free any dirt and waste. Then use a siphon hose or bucket to remove 15-20% of the water.Don’t remove the gravel and rinse it off like you did when you first introduced it to your goldfish aquarium. In an established tank, beneficial bacteria that help regulate the nitrogen cycle have grown and you don’t want to eliminate them from your tank.


Take out your aquarium filters and clean them in the bucket of dirty aquarium water. The filter has these beneficial bacteria too so a few shakes to remove all the debris and a few squeezes of the filter is all you need. But, depending on the filter media, wait a few weeks to make sure the beneficial bacteria in the gravel is back to its pre-cleaned levels and then change the the filter media. If your aquarium filter contains carbon, ion-exchange resins or ammonia absorbers, you should change them every three weeks or so.

Tank Water

You can now complete the aquarium water change in your goldfish aquarium by using tap water and some dechlorinator to eliminate the chlorine. Make sure the water temperature is back to the temperature of what the tank was before cleaning. Place your decorative goldfish accessories back into your goldfish aquarium and then carefully place your goldfish back into their aquarium.

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33 comments on “How to Clean a Goldfish Aquarium

  1. Do u need a vacuum to clean the tank??? I just got some fish for my wedding a week ago and they did not come with anything and when I went to a petsmart they didn’t tell me I needed one to clean the tank.

    • You don’t need one but it certainly helps. If you have gravel on the bottom, a siphon tube really is the easiest way yo remove trapped waste. That trapped waste raises ammonia levels, nitrogen levels and could result in faster algae growth.

    • Don’t use bottled water for goldfish. They actually need somewhat hard water and bottled water is waaaay to soft. Just a bucket of tap water that’s been sitting out for a day or so to release the chlorine is the best for them.

  2. Hiya I just cleaned out my gold fish and I completely forgot that I did not have any of the cleaning liquid you need I had a little drop of one of them but that was it would that be ok ? 🙁

  3. got a new fish tank and ever since i put the goldfish in he seems as though he is weak i put food in for him and he doesn’t seem like he cares. he just lays in his tunnel. put him back in original tank and he is just the same. the reason i got the new tank is because he is getting bigger. i thought that maybe i put too much water conditioner in so i redid the old tank and put him back in it. i’ve had this goldfish for about 2 years and never had a problem before. i hope you can help, my 12 year old is very concerned as am i.



      • It could be several things? you might try a broad based anti bacterial, parasite or fungal medication. which one to use is hard to say. take a look at this page to see if you can narrow it down. In the meantime, do a water change.

  4. Hi! I am new in taking care of goldfish. I got the goldfish last week but then after 4 days, the water is so dirty. By the way, I have nine goldfishes and placed them in a 50 gallon tank with the filter. Is it okay if I take out 2% of the water everyday and replace it w/ an overnight water w/dechlorinator? Thanks

    • Yeah, nine goldfish will dirty the water pretty quick. I would test the water for ammonia and see if the levels are high, if a 2% change everyday is not enough, you may need to do more. Usually people do a larger water change once or twice a week (Your method is a safer method since you are not doing a drastic change each time). But it really depends on the ammonia test results. 50 gallons is a good size tank though, so good on you for that. dechlorinator is a must and letting it sit over night isn’t necessary if you use the dechlorinator but it also doesn’t hurt.

    • It depends on how large your tank is. Doing a partial water change once a week is usually a good idea. Get an ammonia test kit and test the water frequently. When the levels are too high, do a water change.

  5. I have had 3 goldfish now and none over them have lived more then a week. I just have a small one gallon tank and one fish at a time. I’m not sure what I’m doing wrong but each goldfish lived shorter time then the other. The last goldfish died over night and with him i put him in a half gallon tank with just the water in the bag (witch filled the bowl) and i put food in and woke up this morning to a dead fish. I have even tried using bottled water in the tanks i don’t understand what is going wrong. I have never had so many problems with a gold fish.

    • You can’t keep a goldfish in a 1 gallon tank! Minimum suggested is 30 gallons for 1 goldfish. I wouldn’t put any living thing in a 1 gallon tank.

  6. I have had 3 goldfish all at separate times and each one has lived less then a week in my tank and i don’t understand what I’m doing wrong. I just got one the other day that didn’t even make it over night and that one i had in a bowl with the water that was in the bag only. It was a half gallon bowl and a small feeder goldfish. I have never had so many problems with trying to keep a goldfish alive. I have even tried to use filtered water in the tank. I just have a 1 gallon tank with one small goldfish at a time.

    • Buy some beneficial bacteria to help cycle the tank (this helps cut down on toxic ammonia). But really, you need something larger than a one gallon bowl (something with a filter). The water in a small bowl gets dirty really fast which requires frequent water changes.

  7. My 10 gal gold fish tank looses maybe up to a inch of water every week or so from evaporation. When I add water to the tank should I be putting more dechlorinator drops in with the new water?

    • A few thoughts on evaporation. First you still need to perform partial water changes because if you only replace the evaporated water, the contaminants will build up to unhealthy levels. When water evaporates, the heavier particles get left behind. notice how the sides of your tank might have a white residue where the water line used to be; that is the unhealthy stuff left behind. So, when you go to refill your tank, actually remove some of the water too before refilling it.

      Yes you should add dechlorinator but only a small amount. Figure out how much water you add and do the math to know how much dechlorinator needs to be added. Too much is unhealthy for your fish.

      Lastly, if you don’t have a lid to your tank, add one and you will see a lot less evaporation.

    • Yes, you should but make sure you only add as many drops needed for the amount of water you changed. You wouldn’t want to add the same amount of dechlorinator as you would when you first filled your tank up.

  8. Won goldfish at the fair. 3 tiny ones and one that is 10 times larger that the other 3. All of them had a little black on them but 1 tiny one that was solid gold. That one died yesterday. We have them in an approximately 24″x 10″ aquarium. My boyfriend put the tank together and I’m sure he used the.water from trap that was purified with a brita filter, and followed all the proper procedures. Is there anything that may have gone wronsg that we need to change?? Do any other fish live well with goldfish?? Could I just get the bottom feeding fish to clean the tank and never change the water?? Why did that gold one die??

    • Even through a Brita filter I think there is still some chlorine that get through. If that is the case, you need to purchase a small bottle of dechlorinator. The only fish that could live with a goldfish are other goldfish or perhaps cold water minnows. most fish like warmer water while goldfish like water about 70*F. I wouldn’t get an algae eater since they grow large and like warmer water. Goldfish do a pretty good job of eating algae and food particles that have found their way into the gravel. You have to change the water every so often because the ammonia levels can get to unhealthy levels. Buy an ammonia test kit and test the water. If the levels are too high, change some of the water. Don’t just replace the water that has evaporated either because when water evaporates, it leaves behind elements that when concentrated can be unhealthy for your goldfish. So you will need to remove some of the water and replace it with fresh clean water. Best of Luck.

  9. you know when you set up your goldfish’s tank?
    and that you have to put in chemicals, but when you put in the chemicals when you clean your tank how do you wait a couple of days for the chemicals to circulate without your fish dyeing???? PLZ PLZ PLZ ANSWER

    • If you are talking about dechlorinator, something to remove chlorine.. then no, you don’t have to wait. If you are talking about beneficial bacteria that you put in to help cycle your tank, then typically yes. But if you properly clean your tank, you will not kill the good bacteria (ie you didn’t take the gravel out and wash it in the sink or scrubbed the filters.) so you don’t need to wait. Just make sure your ph and water temperature is close to what you had before you changed the water. Buy a ph test kit to test your old tank water and then water you plan to put in the tank. If they are way off, hold off on changing the water until you can buy a ph adjuster. Your local pet store will be able to offer you a solution. even a small change in ph or water temperature too quickly can kill your goldfish.

    • I had well water growing up and used it in my fish tanks and the fish were fine. I sure do miss the taste of that water. Most cities have tap water that has a lot of chlorine and that is what is toxic to goldfish. But well water can have metal or other possibly chemicals i suppose. I would recommend testing your tap water for various things including the ph of your water and see if it’s your tap water is neutral and at safe levels for nitrates, ammonia, metals, chlorine. see these posts for more info aquarium dechlorinator and nitrate poisoning. I’m not sure if distilled water is good or bad thou. I’m told it has a low ph which in that case it’s important to note that a fast change up or down in the ph of your tank water can kill a goldfish. If you need to change the ph, do it slowly.

  10. is it ok to put two small goldfish in a goldfish bowl for the tank cleaning, as long as the goldfish are only there for a short amount of time?

    • I think it’s okay if it’s only for a short time. In the end it might be less stressful on the goldfish to keep them in a goldfish bowl while changing the water as opposed to keeping them in their tank.

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