7 Ways to Fix a Cloudy Fish Tank

Do you keep getting frustrated by a cloudy fish tank? If so, check out our causes and solutions to get your tank clear again.

Jun 7, 2024By Kenny Jarvis
ways to fix cloudy fish tank

A cloudy tank doesn’t always mean the tank is dangerous for your fish, but it can be a sign that something is going wrong. When you add in the fact that cloudy tanks ruin the visual appeal of your tank, there’s no wonder you want to do something about it.

Fixing a cloudy tank can be more complicated than it seems. If there is an underlying issue, the water will quickly get cloudy again. Here, we look at how you can consistently have crystal-clear water in your tank.

Understanding the Causes of a Cloudy Tank

cloudy fish tank
Source: Reddit

Before you start cleaning your tank, it's important to look at the underlying causes of cloudiness. Let's have a quick overview of the most common culprits.

No Water Changes – If you don't ever change the water in your tank, then over time, waste is going to build up, and your tank will get cloudy. Your filter can only do so much, and you have to supplement this with regular water changes.

Overfeeding – This links in with the last point, but if you’re overfeeding your fish, then you are causing more harm than good. This food will decompose quickly and turn into organic waste.

Poor Filtration – Is your filter big enough for your tank? Does it need cleaning? An undersized or inefficient filter won’t be able to remove debris and impurities from the water.

New Tank – Is your tank new? If so, the cloudiness could be caused by it taking time to settle in and not yet having enough beneficial bacteria. As long as your water parameters are safe, this is okay.

Algae Bloom – Excessive nutrients or light can suddenly cause your algae to bloom. This is not only ugly but can make the water cloudy too.

Now we know the common causes of a cloudy fish tank, let’s check out seven methods to fix it.

1. Regular Maintenance

cloudy water change
Source: YouTube

Your first step in addressing cloudy water is to perform routine water changes. This will help to remove any debris that is sitting in the bottom of the tank. For this, it’s best to use a siphon as it can take out that waste along with the water.

The frequency and volume of water you should be changing can depend on the circumstances. However, if you aim for a rate of 20% every two weeks, you’ll be on the right track. If you are struggling with cloudiness. You can make changes a little more frequently until the issue is solved.

Along with water changes, you should also clean your tank. This means scrubbing the walls, cleaning the filter, removing algae and rinsing/brushing any decorations. When cleaning, make sure to not use any cleaning products such as soap or chemical sprays.

2. Adjust Feeding Habits

fish tank feeding
Source: FantaSEA Aquariums

When you put food into your tank, it should all be gone in a few minutes. If it’s not eaten quickly, it will settle into the substrate and start to decompose. A little bit of waste is inevitable, but watch your fish after feeding to see how much of the food remains uneaten.

If it’s all used up, then great, the problem isn’t overfeeding. However, if most of it is settling on the bottom, then start to reduce the amount you are giving them. Set a feeding schedule and make notes until you find the perfect balance.

3. Upgrade/Clean Your Filtration System

fish tank filter
Source: Reddit

When you buy a filter, it should say how much water it is designed to cope with. If your filter is too small for the tank, then it can’t keep up with the amount of waste produced. Consider upgrading your filter to something a little more powerful.

Filters can also get full. Every so often, they need to be cleaned, and the filter media rinsed to allow it to absorb more waste. Your filter media or cartridges may also need periodically replacing to maintain efficiency.

Finally, make sure the rest of your filter is clean. Common issues can be that your intake vents, motor impeller, or outlet tube have been clogged up with junk. Give them a check to ensure they are clear and allow water to pass through.

4. Introduce Beneficial Bacteria Into Your Tank

fish tank bacteria
Source: Bedlam Farm

Bacteria is the underrated superstar of your tank. The right number of bacteria will help to break down organic waste and reduce cloudiness. This will not only make your water clearer, but it will reduce dangerous levels of toxic chemicals in the water.

For established tanks, this is rarely an issue. If you do have a tank that has been working for at least a few months, check to see if you have something in your filter media that will promote bacteria growth, such as a sponge.

If you have a new tank, then you can use bacterial supplements or additives to help kick-start the growth of beneficial bacteria. This is a vital part of the nitrogen cycle that shouldn't be overlooked, even if you have a clear tank.

5. Combat Algae Growth

cleaning tank algae
Source: Aquarium Co-Op

It’s a common misconception that algae are dangerous for fish, and, in fact, there are many species that eat it. A small amount of algae can make your tank look more natural but if left unchecked, it can ruin the visual appeal and make the water cloudy.

The most important first step is to clean your tank often. It's a messy job but is usually easy to remove. The most common culprit of vast algae growth is too much light, so it may be worth considering moving your tank if it’s by a windowsill.

There are also algaecides which you can add to the water, but this should be done with extreme caution. They can kill shrimp, kill your live plants, and disturb the water balance of your tank. It’s better to choose a more natural method of algae removal.

6. Test Water Parameters

water testing strips
Source: YouTube

Regardless of how your water looks like, it’s always important to test the water. Testing strips will show you crucial water parameters such as pH, ammonia, nitrite, and nitrate. They can also show you other indicators such as water hardness and carbonate.

Knowing these parameters can give you an indication of why your water is cloudy. For example, if the levels of nitrate are high, then an immediate water change is required. If the parameters are healthy, then you can fix the cloudiness and have peace of mind knowing that your fish are healthy.

7. Utilize Chemical Clarifiers

planted fish tank
Source: Reddit

The final step you can take is to use a chemical clarifier, usually in the form of liquid drops. These work by binding suspended particles together, making them into bigger clumps. This makes them easier to remove through water changes or your filter.

These are usually safe to use but you need to strictly follow the instructions to ensure it is safe for your tank and you’re not using too much. After any chemical treatment, it’s important to closely monitor your fish to ensure they don’t have adverse effects.

Kenny Jarvis
By Kenny Jarvis

Kenny is a passionate animal lover who finds joy in the diverse world of pets. He frequently embarks on zoo adventures with his children, immersing himself in the wonders of nature. At home, Kenny tends to a much-loved aquarium, nurturing a thriving underwater ecosystem. Through his passion for writing, he aims to help fellow animal lovers create happy and healthy environments for their pets.