What Causes A Cloudy Fish Tank

Everyone loves a nice clean fish tank, but sometimes your perfectly clean tank can become a cloudy water mess. In order to return your tank back to its former glory, you first have to understand the causes of a cloudy fish tank. There are three different water colors of cloudy fish tanks and each have their own causes. Depending on the type of cloudy water you have, there are different things you can do to help clear the water up. Whatever the cause may be, you must first correct the cause before you can keep your water clear.


White Cloudy Fish Tank

White Cloudy WaterA cloudy fish tank that looks white or milky, is usually caused by a bacteria bloom. This is usually the most common type of cloudy fish tank water. This can happen if even one time a lot of extra food was dumped into the fish tank or through regular over feedings. Other causes could be if a fish died and wasn’t removed from the aquarium or if your fish tank is still cycling. Depending on what is causing the cloudy water, there are different things to do that can fix it. First, you need to correct the cause, so if you have been over feeding fish or if there is a fish that died, the problem should first be corrected so the water doesn’t continue being cloudy after you clear it up.

Once the initial cause is corrected, you can clear the water and keep it clear. The best way to fix your cloudy water is to perform water changes. Start by doing 20% water changes twice a week and if after 2 weeks or so the water is still cloudy I would then recommend performing a 50% water change weekly until the water stays clear. When changing the water, make sure you are using a good water conditioner to treat the water. Never remove all the gravel and change it with new gravel, this could potentially kill all your fish by causing your tank to re-cycle. If after doing all this your water remains cloudy, you should consider testing the water you are putting into the tank, whether it be from the tap or bottled water.

If the problem is the fish tank is still cycling, tanks between 2-6 weeks old, then you really just need to give the tank time and it should correct itself. However, you could do water changes as described above to help clear the water, although likely doing nothing will have the same affect in the same amount of time.


Green Cloudy Fish Tank

Green WaterA cloudy fish tank that is green in color is typically caused by an algae bloom. This is different than the algae that grows on the glass of your fish tank, this is specifically algae that grows in the water column. Green cloudy water from algae is usually caused by excess nutrients in your fish tank or too much light on your fish tank. Both of these causes have easy fixes that can help clear your water quickly. Excess nutrients are caused by either, overfeeding, overstocking, or poor maintenance. Overfeeding is easily corrected by reducing the food you feed your fish. Overstocking is a little trickier, but essentially you need to remove some fish and either give them to a friend or give it back to the fish store. Poor maintenance is corrected through performing regular water changes to remove the excess nutrients.

If you have too much light on your fish tank, you could have an issue with green water. Lights that are running for more than 10-12 hours each day, can contribute to green water. Also, if your tank is near a window that is getting sun, this can cause algae blooms as well. You should make sure you are running the aquarium lights for the correct amount of time and that sun does not shine directly into the fish tank.

Regardless of the cause of the green water, you can correct it by turning the lights off and keeping the fish tank dark. Usually keeping the lights off for a few days will clear green cloudy water; however it’s important to make sure the underlying cause has been corrected otherwise the green cloudy water will return. Since algae is a plant, by keeping the lights off, you are killing the algae growing in the water column by starving it out. If you have a planted tank, use this method with caution since your plants also need light to survive. Hardier plants won’t be affected, but if you have any more fragile species you might want to try a different route.


Yellow Water Fish Tank

Clear WaterYellow WaterWhile your fish tank may not look cloudy, you may notice a yellow tint to your aquarium water. This can be a result of a few things; driftwood leaching tannins, decaying plants, or some other organic matter. Depending on the cause of the yellow water, it may actually be beneficial. If you think of lake or stream water, it is very rarely crystal clear, many times the water will have the yellow tint to it. This is the same as what is happening in your fish tank. Driftwood is naturally leaching tannins into water which is turning it yellow. Fish which come from lakes and rivers where this naturally occurs, can be more calm when water is tinted in home aquariums. The tannins also can drop the alkalinity and hardness of your aquarium which makes the water chemistry more natural for most tropical fish.

If even after hearing the benefits of the tannins in driftwood you still would like to remove the yellow tint, performing water changes is the best course of action. Eventually the wood will stop leaching the yellow tint, so over time by doing water changes your water will become clear. Also, if you boil the driftwood this will help speed up the process of removing the tannins in the water. If the yellow water is from decaying plants or some other organic matter, it is best to remove that and perform water changes. This will help get the water clear again.

No matter what type of cloudy water you have with your tank, before you can correct it long term, you must first fix the underlying cause. After you have fixed the underlying cause, besides doing water changes, another option are UV Sterilizers to keep water from becoming cloudy. These work very well, and as long as you have fixed the underlying problem, and could be added to your tank to even help maintain the health of your fish. Besides killing algae and bacteria blooms, UV Sterilizers also can kill parasites and pathogens in the water that could harm your fish. I have personally used the Green Killing Machine UV Sterilizer in one of my tanks, and had good results with clearing an algae bloom fast.

This is box title
AA Aquarium Green Killing Machine

• Say GOODBYE to GREEN and HELLO to CLEAN. AA Aquarium’s Green Killing Machine eliminates cloudiness, algae & bacteria to give your fish the crystal clear water they need for perfect health!
• The #1 UV in the US – over ½ Million sold. Patented technology that no one else has and the ONLY UL Safety Tested internal UV kit – Be safe with your tank and fish!
• Patented Sealed UV BULB – you never touch glass! Chambered bulb assembly for high water dwell time and outstanding efficacy! No gloves-No mess-EZ bulb changes!
• NO TOOLS REQUIRED! 10 minute installation – Follow simple steps to get clear water in days. No Guessing – Control Box LED tells you when to change bulbs!
• 3 Year Warranty on Pump; 4 pcs sponge pre-filter; Pump rated 220L/Hour. Perfect for aquariums up to 50 Gallons (210 L). UL/cUL Listed

Hopefully you have found this helpful and if you have a cloudy fish tank you can use this article to clear your water.

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