The importance of clean water can’t be stressed enough when it comes to caring for your fish.
If you want a healthy goldfish, you have to start with healthy water.
Usually the water we start out with is clean…
… But it sure doesn’t stay that way.
(You know what I’m talking about if you’ve owned a goldfish for any length of time.)
They eat, they poop, and the nitrates rise.
So, this means we’ve got to roll up our sleeves periodically and change our goldfish’s water.
But don’t worry:
Today I’m going to show you how to do this the EASY way.
How to do a Small Water Change for Your Aquarium
Small water changes are ideal to maintain already low nitrate levels periodically.
Depending on your setup this may be all you need, especially if your tank is not very dirty and your stocking is light.
And, of course, if your water quality is already on point or close to it.
Note: This WILL take forever if you intend to do a big water change or if your tank is over 40 gallons! See the section after this on how to do a big water change instead.
- A 5 gallon bucket
- Siphon & Squeezer
- Water conditioner (I use Prime)
1. Disconnect the power source
All heaters and pumps should be unplugged.
Not only does it prevent your equipment from burning out…
… It protects you in case of a water spill.
Done?
Great!
2. Start the siphon and vacuum into the bucket
With one end of the siphon in the tank water and the squeezer end in the bucket, begin squeezing the rubber squeezer rapidly.
This will start the water flow from your tank to the bucket.
Tip:
It seems to work better if the end is pointed up, and best if both ends are under water.
Now that your flow is going, it’s time to pick up the debris from the bottom.
If you have a bare-bottom tank, this is pretty straightforward.
Anything on the bottom will probably have the most waste trapped under it, so it is time to pick it up and vacuum underneath.
If you have sand, it’s still pretty easy.
You can gently swirl the end of the siphon over the sand to stir up the debris and vacuum it up.
Now, if you have gravel, you need to plunge the entire end of the siphon as far as you can and try your best to get all the debris out.
Sadly gravel is quite difficult to clean and there’s really not an easy way around it. (I recommend removing it and using sand or bare-bottom instead for your goldfish – you will be shocked how much easier it is to clean.)
3. Dispose of the bucket water
Is your bucket full yet?
Time to stop vacuuming (just remove the siphon from the tank) and dump it out!
Here’s a secret:
Plants LOVE this waste water from your tank.
Instead of putting it down the toilet or sink (which you can still do), I recommend watering your garden if you have one.
- Repeat this process from step one until you have removed how much water you want (typically 10-25%)
4. Refill the bucket with clean water & condition
It’s time to refill the bucket with clean water now 🙂
Be sure to match the temperature to within 2 degrees for your goldfish.
I use a digital thermometer for this part because it is usually much more accurate than testing by hand.
Now you need to add your water conditioner (I like Prime the best).
If your water source is too acidic, now is the time to put your buffer in as well.
You can give it a few good swirls with your hand or the siphon end to mix it up nice and thoroughly.
5. Add the new water into the aquarium
Lug your bucket to the tank, trying your best not to slosh the water all over the floor, and carefully – and SLOWLY – pour the water in.
And there you go my friend.
You’re all done!
How to do a Big Water Change for Your Aquarium
Okay, so the method above is great for when you need to do a small water change, but what if you need to take out and replace a LOT of water?
You will probably end up breaking your back.
Yikes!
Many goldfish keepers really need to do 50% or more water changes at least once every week.
And if your tank is over 20 gallons, that’s a whole lot of buckets to haul.
Not everybody has the strength – or time – to do that.
But don’t panic:
I have the strategy for that too that involves much less effort on your part.
- Aquarium water changing kit (I prefer the Python No Spill Clean N’ Fill)
- Water conditioner
- Pump (optional)
Video recap:
1. Connect the faucet adapter & green plastic pump to the sink
You will probably need to unscrew the default aerator on your sink.
Then screw the brass connector in its place.
Done?
Now you screw the bright green plastic pump onto the brass connector.
2. Put the other end of the siphon into the water
This is pretty straightforward (I hope!) 🙂
If it’s not in the water it won’t be able to suck anything out.
3. Start the drain process & vacuum the waste
Sink method
For this method, just turn on the sink and the suction of the water coming out will start the suction.
Make sure it is in the “drain” position before you turn the water on and start the suction.
Now you can use the end in your tank to pull up the waste.
Don’t forget to get those really dirty spots under anything in the tank 🙂
Pump method
If you don’t want to waste so much water…
… Or if you have a pretty big tank…
… Or you want to change out a lot of water in a much SHORTER amount of time…
… The pump method is for you.
Instead of turning on the sink and wasting perfectly good clean water, you remove the hard plastic tube and connect it to a submersible pond pump.
This takes out a lot of water FAST.
That said:
With the pond pump, you won’t be able to get waste out of gravel or do as good of a job vacuuming up the poop.
But if you use good mechanical filtration with a bare-bottom goldfish tank, you probably don’t need to vacuum up the debris much anyway.
It really depends on your setup.
4. Switch off sink & condition the water
Once you’ve taken out how much water you want, it’s time to turn the sink off.
Good job!
Now you just need to condition the water and refill.
Unlike with the bucket method, just measure out the full amount of water conditioner for the volume of your tank and put it straight in the water with your fish.
Don’t worry:
This strong water conditioner concentration will soon be diluted and won’t hurt your fish temporarily.
5. Refill the tank
Is your tank conditioned?
Perfect!
The last step is to refill the tank with fresh water.
All you have to do is change the green pump to the “fill” position and start the water flow.
Don’t forget to match the temperature (important!).
And you’re all done!
Conclusion
This was a simple run-down of how to do water changes for your goldfish tank.
There are more complex ways to do it, such as aging & aerating the water first before you refill, but not everyone wants or needs to do that.
I bet you feel much better knowing how awesome of a goldfish owner you are by giving them nice clean water!
Great job on all your hard work – it’s totally worth it!
Now I want to hear from you.
Do you have any tips you’d like to share?
Got a burning question?
Leave your comment in the section below.
Featured Credit: Chaikom, Shutterstock
Great post, thank you!
But you should know that it is not necessary to keep the tap water on when draining the aquarium with the python system. Once the siphon has started and the aquarium water has made it all the way to the sink, you can simply turn off the tap and …. the aquarium water continues to drain! However this method will only allow the water in the aquarium to drain as far as the height of the tap. I prefer to pinch the tube, unscrew it and put it down in the bathtub and can drain as much as I want. Plus, this method makes it way easier to clean my filters.
Great tip! Glad you liked the post 🙂
hi there! is the Fluval Hagen Biological Enhancer good enough? i dont have any alternate ooptions where i live unfortunately.
That’s one of the better quality ones.
Hi ! Some say that’s a good idea to add a bit of aquarium salt on a regular basis, what are your thoughts on this topic ?
If you do it, I would rotate. So 2 months with salt 2 months with none. This will give the fish a break.
I just bought 2 goldfish from petsmart and ever since I brought them home they have been gulping air from the top constantly and it has been a week. Unfortunently I didn’t start researching about goldfish until the day I brought them home, but I have been doing 50% water changes every day and whenever I test the water the ammonia and nitrite are low and the PH is at 7.3. I have a 20 gallon tank with a bubbler and filter and I treated the tank with API melafix. What should I do to make my fish stop gulping for air.
Low ammonia and nitrite, or 0? If its 0, you could be dealing with parasites.
Hi meredith, i have a pearscale named Emma, and her fins are turning BLACK. I am SURE THIS IS NOT NORMAL, and is extremly concered about my DARLING fish. Pleaseeeee help thanks, Norma
Test your ammonia, this is almost always from that.
I recently bought 2 goldfish a week ago and they have constantly been gulping for air. I keep doing water changes and testing for ammonia and nitrite and there hasn\’t been problems with it and the PH is 7.3. I have a bubler and a 20 gallon tank, I also treated with API melafix. How can I make my fish stop gulping for air?
You might need to start considering a parasitic issue.
Hey Meredith, my fish is called mnm stands for moldy mandarin. I know, it is such a bad name. But yeah. Anyway i got him at walmart yesrerday but i relized i was not prepared and now i dont know what to do. He seems heathy, and is a what they called Shubunkin.
You can start here if you want with our care guide 🙂
Hello Meredeeth
I am 7 yeers oldd. I Havve a fissy named Bubbe. He is cutte. But he is sickk. That is whye i need yor help. My mummy sad he will diee. But i dont want himm to diee. Please helpp. He cant swimm. My mummy wont get help. So ii have to. Bubbe iss da beest fishy eveer. I also havve a doggie called baila and some mice called snowy and ivy. My mouse roo die when i was 6.
Pleese help. I got bubbe wen i was 5. I think bubbe iss 1 year old. When do fishies die. I think bubbe is too young.
Pleese help pleeeeeeeeeseee.
Thanks so much by da way the email is my mummy’s.
Ava
Hi Ava! Most goldfish live a minimum of 5 years for their whole life. You can start by taking a sample of your water to the pet store to get it tested, and see what they say. That’s where I usually start.
I’m planning on getting a single oranda in a 20 gallon tank- bare bottom, a couple of fake plants. What percentage of water and how often would you recommend to change weekly? I want my fish to be living in the best possible conditions.
Also I plant to cycle the tank with the fish by using Seachem Stability, testing daily for nitrates and placing an ammonia sensor inside the tank. During the cycling process what amount of the water should be changed?
Depends on your water test results once the tank is established. If your fish is in the water during cycling 50% daily is good.
Hey Merridith,
My name is Jhon, and i am concerned because my goldfish died for no reason yesterday. I found him on the floor. There is a lid on the tank, so i have no idea how he jumped out. How did this happen? Btw i love your blog
If there’s any kind of opening the fish could have jumped through the back there. I’ve had one fish jump out 3 or 4 times for no apparent reason and had to try many lid variations.
Hi Meredith.
Thank you for your very informative post on how to care for goldfish. It’s one of the most helpful ones I’ve come across.
I have a question when doing water changes. Is it necessary to add a bacteria formula with every single water change? I’ve been adding conditioner and the bacteria formula with every change but I’m getting worried I could be adding too much?
Typically the time to add bacteria is with each water change, as you are doing 🙂
How can I sanitize my python after using it for my quarantine tank so I can use it in my display tank? Thanks!
I run vinegar diluted in water 1/2 cup per 5 gallons through it, you can use a submersible pump attached to one end.
What do I need to test for in tank water, I have a kit for nitrites, nitrates, ammonia, and ph. Is there anything else I need to know? Thanks!
GH & KH are good to know also.
Hi Meredith, I was wondering if you could help please, I have a goldfish in my tank that has a swollen side, the fish has been like this for about ten days, it makes him look slightly curled outwards towards the swelling side, he is otherwise health, swimming and feeding ok, this morning I looked and it looks like a pronounced cyst or something is protruding from the center of the swelling, any ideas as to what it could be and if it’s fixable, if it bursts will it effect my other fish, I would be most grateful for your advice please.
Graham
Sounds like a bacterial infection. I would put him in a hospital tank & treat with antibiotics.
Thank you Meredith, I shall do as you say and see what happens, this web site is awesome by the way, such great information from you.
Hi meredith!
I got 2 goldfish for my sons’ first pets! Hes 5. I know goldfish, so I’ve heard, are easy to die. Love your site, and trying to learn to keep them living longer. Wish I would’ve found your site first, Before getting the fish. Needless to say I have a 2 gallon tank, for two goldfish. No filter was suggested. I’ve learned from you, I may need to change the water sooner, and by prime ASAP. If I change a little bit of the water out at a time. And get prime added. Will I still need to get a filter? Or is it too late? We have blue colored plastic looking stones , in the bottom, and a very small castle. $50 in, not wanting to go crazy. But just would like my sons first pets to live a little longer as much as we can.
Some people rely only on water changes. But it is usually required each day or every other day depending on your feeding if you don’t have a filter. You can get a small carbon filter like this one pretty inexpensively. Goldfish are easy to die but it is usually because they are sick to start with, with slowly progressing disease. But if you get lucky with a healthy one they can live a long time.
Hello! I am making a jump into the fancy world with a 150 gallon tank (I’ve almost always had tanks in my life, but never with goldfish) and do you have a recommendation for the easiest way to conduct the water changes on that size of a tank, when I am roughly 65 feet from the closest sink? I’m always nervous about hoses going across the floors, but I would imagine that they make really long hoses, because I can’t be the only person on the planet with this issue.
Python makes a 100 foot hose that would be ideal for your situation.
Thanks for the information. I was told to change 25% and now know that is probably why my 14 year old shubunkin is getting septicemia. I’m going to get a Python hose to make the changes easier. I have a sink about 10 feet away. I had no idea I could had the Prime first to the remaining tank water before the tap water goes in.
Glad you found the post helpful, Terri!
Hi there I have a 200lt fish tank cold water and it always goes cloudy water I been doing 50 water change water change they have meal in morning and night do I need do more water change
Cloudy water is usually a bacteria bloom. It may settle on its own but it may take a while. A UV sterilizer will stop it.
Hi!
Can I do a 90% water change? My water in my bowl (I am saving up for a bigger tank) got dirty after one day and my fish was gasping for air. I have a plant and air stones and I regularly get a cup and poor the water back in to try put air in the tank.
I just changed the water nearly completely and I added special stuff that the pet store gave me to make the tap water safe. My fish is instantly better but I’m scared that the water change might be a shock?
Could you tell me if a 90% water change every 2 days with no pump is too much?
Yes you can, just match the temp. You can do them daily.
Hi I have a 125 L tank with 5 Goldfishes recently 2 died and for me it looks like a swim bladder issue. I came into this conclusion because the fish was sinking to the bottom. All my water parameters are ok, can you let me know whats the cause for this- is it a bacterial infection.
Do I need to treat my other fishes
Could be. You might want to check out this post.
Hi I have inherited a 9cm pond gold fish and have purchased a 40 litre tank with a filter. It seems to be quite happy, but wondered if I could add another fish to the tank and if so could I purchase one that is in a tank? Should I get one of equal size? Thanks in advance.
Sure, and yes. I would quarantine first, whatever you decide to do.
Thanks for the great tips on your site! I brought home a pearlscale goldfish (4in) a week and a half ago and have been doing 90% daily water changes. Is this too much or should I keep up with the large water changes? My tank is on the smaller side, 10 gal, so I know it will get dirty faster than most.. Nitrite levels have not been above .5 and I add appropriate doses of Stability and Prime with each change. The temperature does not vary more than two degrees. Should I add anything else by Seachem to the tank to help with water purity? I have some marimo plants, and can purchase more of those, but don’t want some of the taller plants. Thanks so much!!
Not too much, sounds good. You’re doing the fish in cycle sounds like. Shorter plants are anubias & java fern.
Hey Captain, I have a question on chemicals. I\’ve read your stuff on Dr. Tim\’s, Stresszyme,and others, I\’ve tried it, and they work wonders. However I have to ask if there\’s too much put into the tank. Dr. Tim\’s is a weekly dose, stresszyme is a weekly dose, algaefix is weekly, at what point is there too many chemicals in the water? Or is it good to dose so much stuff into the tank weekly, with regular water changes?
I don’t use anything but Dr. Tim’s probiotics personally. I try to minimize the chemicals.