There are a couple of things that could cause white cloudy aquarium water. The good news is that they are easy to treat once you narrow down the cause. Dirty substrate or decorations, or a bacteria bloom are the usual suspects.
Dirty Substrate or Decorations
This is very common reason for cloudy aquarium water in newly set up fish tanks. It is important to thoroughly rinse your aquarium substrate and decorations before putting them in your tank. If you believe this is the reason for your cloudy fish tank water, there are a couple of things you can do. Give it a couple of days and you should notice that the particles fall to your fish tanks floor leaving clean water behind. If this doesn’t happen on its own you should start 20% water changes until your water clears.
Is a Bacteria Bloom the reason For My Cloudy Aquarium Water?
Did you just do a large water change? Have you just thoroughly cleaned your tank? Have you just medicated you fish? Have you just set up your tank? All of these things can sometimes cause a bacteria bloom. If this sounds your situation, you the best advice is to sit back and wait. When those bacteria establish themselves, your cloudy aquarium water should clear up on its own.
Just Give it Some Time
As you may have noticed the basic treatment for white cloudy aquarium water is to hurry up and wait. There are chemicals available but they are not recommended. White cloudy aquarium water will almost always clear up on its own.
20 responses so far ↓
1 Candace // Oct 14, 2007 at 12:05 pm
We bought a new 77gal tank, pre-washed everything, added a couple of dozen gold fish let them sit for a couple of months before we add more expensive fish. Went away for a week the begining of Aug and came home to a total green tank? We changed the water and did all the treatments, water testing etc…it seems within a couple of days the water starts to go cloudy then if we leave it long enough it will go green.
If you could give us some addvice that would great!
Candace
2 Eric // Oct 15, 2007 at 7:04 am
Hello Candace,
The trick to beating aquarium algae is getting rid of any excess nutrients. This will starve the bacteria and get rid of your algae problem. You can find some tips here http://www.fishtanktutor.com/how-to-fix-green-aquarium-water . Frequent water changes and a chemical treatment should do the trick over time.
3 Diane // Nov 15, 2007 at 10:38 am
Great, informative site! I have a 10 gal. tank with 13 African Dwarf Frogs and some Mollies and live plants. Everything is fine and dandy UNTIL I do a water change. Then immediately I get white smelly water. The last time this happened I did a 25% water change twice a day because the water got so bad. I had to move the Mollies to another tank because they were dying. Luckily the froggies survived although the water got worse and worse. Finally, I pulled the whole tank apart and washed the substrate, a clay and stone mixture 2″ deep. And planted new plants. That seemed to clear things up. The plants are growing nicely as I have a co2 maker on a timer. I added back some Mollies after a bit and everything has been going along great, no problems, no water changes, for weeks. The other day I was feeling guilty because I read so much about water changes so I changed 20% of the water (with conditioner of course) and rinsed the filter and that very evening the water started to get white and now it is getting smelly again. The Mollies were all at the top, even though a PH strip said everything was within normal ranges. I removed them again to be safe. The water isn’t as smelly as the last time but it looks like it will get worse. It seems like the initial water change throws my tank in turmoil. What am I doing wrong? Thank you so much for your help.
4 Eric // Nov 15, 2007 at 11:03 pm
Hi Diane,
Sounds like a classic case of a bacteria bloom. What’s happening when you deep clean you tank and filter is that you are removing the good established bacteria that is necessary to keep your aquarium balanced. Drastic water changes, filter replacements, substrate cleanings are all disruptive to your bio filter.
Take a look here for a little more detail on it. http://www.fishtanktutor.com/the-3-most-common-aquarium-cleaning-mistakes & here http://www.fishtanktutor.com/deep-cleaning-a-fish-tank-in-4-easy-steps.
For now, I would just try to keep your nutrients under control and give it some time. Nutrients just feed the problem. You can also find some products that help control nutrients at your local retailer if you want to speed things up a bit.
5 APRIL // Feb 8, 2008 at 10:22 pm
Thank you so much for this site, Eric! I followed your advice and my tank looked less cloudy IMMEDIATELY!
6 tinkrbrr // Feb 10, 2008 at 11:00 pm
I have an aranda lion head. I saw the plecostomus,s in my tank suckering her side, which caused red circles like blood blisters, but skin not broken. I got rid of the plecos, as they were very big. I treated the tank for 5 days for her sores and she seemed Ok. Now she has 2 big round red sores with canker looking skin around it on the same spot I also have a Koa with her , same size, that has a small orange swollen spot of her side. There are no more fish to harm the others, as I have watched them closely Help, as I have no idea what to do.
7 Eric // Feb 12, 2008 at 8:04 pm
Great to hear April!
8 Eric // Feb 12, 2008 at 8:13 pm
Hi Tinkrbrr,
The red sores sound like a bacterial infection. Frequent water changes are very helpful in working on the root of the problem. If it won’t clear up on its own after some good maintenance, you can find many antibiotic options at your local retailer. The most popular active ingredient is Tetracycline.
9 steve // Feb 21, 2008 at 11:06 am
I have a 30 gallon tank now after battleing a green tank for a long time the water was crystal clear and now it is starting to get cloudy I did a partial water change. but i also added more fish in to the tankabout a week ago. What should i do to fix this
10 Eric // Feb 24, 2008 at 2:42 pm
Hey Steve,
You might try some bacteria starter. Depending on how aggressively you worked on clearing up the algae, you may have disrupted the already established good bacteria.
11 volker // Feb 24, 2008 at 8:01 pm
i have a 4 year old 46 gallen tank. i have 3 clown laoches , 3 tiger bards and 2 gromies plus one large alge eater. the water in the tank whent cloudy about 2 weeks ago and i can’t get it to clear. have done 2 water changes. any suggestions?
12 Eric // Feb 29, 2008 at 3:26 pm
Hi Volker,
If there have been any big changes that may have disrupted the bio-filteration you should add some bacteria starter. Changing the filter, big water changes, and some chemical medications can do this.
13 chris // Mar 14, 2008 at 2:58 pm
I have a 30 gallon tropical community tank with a few danios, some platys, some mollies and a pleco and my water is very cloudy. I have been doing 10% water changes daily as recommended by other sites but my water is still incredibly cloudy. Any suggestions?
14 Eric // Mar 16, 2008 at 3:32 pm
Hello Chris,
Bacteria blooms usually work themselves out over time once the good bacteria builds back up. I’d suggest bacteria starter to move things along. Also, don’t do anything too disruptive to your bacteria. You’ll want to steer clear of filter changes, big water changes, and medications if possible until it re-establishes itself.
15 Honus // Mar 17, 2008 at 12:55 am
Hi everyone,
I am a newbie. I just setup my tank about 2 weeks, i have 5 oscar in a 72g tank. the water gets little cloudy. I change it 15% every 2 days. however, i notice some white stuffs on the fish and it seems to do manage the fish fins and tail. the fish act normal, eat, swim around. Do anyone have any idea what problem I have. i want to do the right thing. Thanks.
16 Eric // Mar 20, 2008 at 8:17 pm
Hey Honus,
The cloudy water is probably caused by the un-established good bacteria. As for the white on the fish, you might be dealing with Ich.
http://www.fishtanktutor.com/kill-fish-ickich-in-4-days-flat
I wouldn’t react yet with treatments until you see other signs of sickness. If your fish are lively, they probably aren’t stressed. The problem is that the treatments can be harmful the set-up of your tank.
17 kolby // Apr 5, 2008 at 8:01 pm
Hello, i just sat up my tank a week ago and everything is doing really well. But i just noticed yesterday that my water is starting to get cloudy? What should i do?? is it because its a new tank?
18 Eric // Apr 8, 2008 at 8:44 pm
Kolby,
If you are sure it’s white your best course is to just wait it out like described in this post. Take a white cup and dip some out to make sure. Sometimes algae just looks cloudy until you look at it against white. Then you notice the green. If it is green, take a look here
http://www.fishtanktutor.com/how-to-fix-green-aquarium-water . There’s a lot of info.
19 random dude // May 6, 2008 at 8:49 pm
i have a 20 litre fish bowl and every time i change the water(20 percent) in the tank the water stays cloudy. I just can’t seem to keep the water clear. Cpuld you help me with my problem. I have 10 3 cm gold fish and one 2 cm mornada. Also how many fish can i hve in my tank per litre
20 Eric // May 7, 2008 at 9:46 pm
Take a read through here for fish count. Sound like you are a little heavy.
http://www.fishtanktutor.com/how-many-fish-beware-of-the-rule
To kick the cloudiness you’ll need to ramp up the % change. If you’ve been doing 20%, try 50% every other day, then work on the cause.
http://www.fishtanktutor.com/how-many-fish-beware-of-the-rule
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