Why Does My Fish Tank Get Dirty So Fast? Causes and Solution

If your fish tank starts to look murky and dirty after a few days, you are not alone! This can happen in even the most well-maintained aquariums. In this article, we’ll figure out why that is—and how to stop it from happening.

The more you know about what could be causing the dirtiness, the better off you will be. It could be something simple like poor filtration or a bad water source, but if left unchecked it could lead to serious problems like salt buildup which spells disaster for your precious aquatic creature friends.

Luckily, there’s an easy answer: periodic maintenance! Doing regular upkeep on your aquarium can keep it sparkling clean in between feedings and filter changes.

Why Does My Fish Tank Get Dirty So Fast

Why Does My Fish Tank get Dirty so Fast?

Fish tanks can quickly become dirty if not maintained properly. This can be a source of stress for your fish and even shorten their lifespan. Fortunately, there are several common causes that make your tank dirty so fast, and we’re going to help you pinpoint them!

When the aquarium walls start to develop in a brown or green shade, it’s time to address the problem. You will want to act quickly and efficiently to determine why your fish tank is becoming dirtier and dirtier by the day.

The most common reasons why an aquarium gets dirty so fast include overfeeding, poor filtration, overcrowding, inadequate water changes, low-quality substrates, inadequate decorations, and dead plants. If you suspect any of these factors in your fish tank care routine, you should take the necessary steps to fix them right away. Otherwise, seek advice from a reputable local pet store or hire professional services for a thorough cleaning of your tank.

By understanding what causes an aquarium to get dirty quickly and taking proper measures to prevent it from happening again, you can ensure a healthy environment for your freshwater fish – one that can last for years!

Improper Filtration

Improper filtration is the main source of a dirty fish tank. In simple aquarium setups, hang-on filters should be changed frequently. This usually means replacing the filter media every month. If not, the surface will be noticeably covered in black and brown particles – a sign that it requires renewal.

For more difficult aquariums with sump tanks, such as saltwater aquariums, there may be clogging in the plumbing due to excess food waste from overfeeding your fish. This makes filtration less efficient, preventing it from properly removing harmful components from the water. To fix this problem, it’s important to check the plumbing and immediately remove any build-up found inside.

Lack of Water Changes

If you have a freshwater fish tank, then water changes are an essential part of keeping your fish healthy and the tank clean. But if you fail to do regular water changes, you might notice that your fish tank gets dirty much faster than usual.

That’s because inadequate water changes mean that contaminants don’t get removed from the water column, leading to rapid accumulation of debris, algae growth, and higher levels of ammonia and nitrites – all dangerous for your fish!

Luckily, it’s fairly simple to do a water change: First, measure the temperature and pH of your tank before removing a percentage of the old water with a bucket or siphon. Then replace it with dechlorinated tap or purified aquarium water. And don’t forget to add any required medication or supplements to keep your fish safe and healthy!

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How to Complete a Water Change

Conducting water changes is an important part of keeping a healthy aquarium. To start off, remove all the decor that isn’t alive from your aquarium and use a soft brush to wipe down any plants you have in there. If you have any decorations like rocks or gravel, you’ll need to use a more intense brush to remove any build-up of algae or particles on it. Keep those items next to the fish tank while you do the rest of your water change.

Once that’s complete, use a siphon device to get rid of additional waste in the substrate of your tank. Depending on the size of your fish tank, you may find this more difficult for larger ones so make sure to cover every surface area possible. Don’t be alarmed if you notice dark brown or black color coming out from the gravel — this is perfectly normal when removing waste! However, if it’s the same color in your main aquarium water then that is something to be worried about.

Next Steps

The next step in your aquarium care is to change out the water with a siphon. Use the siphon to remove about 30% of the components from your fish tank and be very careful not to accidentally suck up any of your swimming fish – there are stories where that has happened and most fish survive if they’re noticed, but there can be rare cases where they don’t. Once you’ve removed the water, dump it somewhere safe and make sure that this location follows local laws regarding dumping water.

The last step is to replace the dirty water with clean filtered water from a bottle or jug, not regular tap water! Tap water needs to go through a filtration process, which includes using some chemicals, so always add conditioning and proper chemicals before using them in your tank. Remember also to watch out for temperature when replacing aquarium water; it should match the temperature of the old environment to provide a comfortable home for your precious fish.

Overfeeding the Fish

It’s easy to get carried away when feeding your fish, given their inability to say “enough.” As aquarium hobbyists, we tend to want to make sure that our fish are well-fed and taken care of. But it’s extremely important to keep in mind that the stomach of a fish is only the size of its eyeball – it doesn’t take much for them to be satisfied.

For some species like Goldfish, you need to be particularly careful because they never seem to stop eating when food is presented! This makes it very easy for them to become overfed if you are not careful.

That’s why, when feeding your fish, it’s best practice to use chopsticks or other similar tools so that you can give the proper portions. And next time you feed your aquatic family, think back on this article and remind yourself to portion sizes in check!

Direct Sunlight

Direct sunlight is the enemy of a healthy aquarium. If your aquarium is positioned near a window or door, the light from the sun will eventually cause more than just regular and hair algae to grow on your walls and decorations. The light from the sun will also add to the light inside your fish tank, which could be a dangerous combination for your fish’s health.

Therefore, if you find that your aquarium is receiving direct sunlight, it’s essential that you look for an alternate placement for it. Of course, sometimes this can be a daunting task so don’t hesitate to reach out to your local fish store for assistance—they usually have maintenance teams who are experienced in moving large aquariums at reasonable rates (typically about $90 an hour).

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Solutions for Treating Cloudy Aquarium Water

If you have cloudy aquarium water, the good news is that there are five effective ways to get rid of it and make your tank crystal clear again. The first is proper tank maintenance: making sure you’re replacing the water regularly and cleaning out filters and other items in the tank.

Proper Aquarium Maintenance

Proper maintenance of your aquarium is the key to preventing cloudy water issues. If things get out of control, then it may take multiple water changes to get back into balance. That being said, a regular routine with regular water changes is the best way to keep healthy aquariums.

When doing a water change, it’s important to also clean your substrate with a gravel vac. This removes any debris or nutrient-rich particles from the surface of your tank and helps you maintain clear, healthy water free of excess food and waste materials. Doing this regularly helps keep everything in check and can prevent cloudy aquarium issues before they even appear!

Making Sure Your Glass Is Clean

Making sure your tank glass is clean is an essential part of having a healthy aquarium. A great way to do that is to use a safe cleaner, such as white vinegar, and Magic Erasers to tackle water stains on the outside of the tank. Get rid of those smudges without risking any chemicals leaching into your aquarium!

Another option for cleaning the inside of the tank is to use a razor blade or Flipper Cleaner. The Flipper Cleaner is especially great since it can easily be manipulated from outside the tank – getting your kids involved in keeping their tanks clean at the same time! Plus, they come in fun shapes and designs – kids love them! It’s powerful enough to scrape off even tough algae buildup, leaving you with spotless glass. Keep up with regular cleaning, and you’re sure to have crystal-clear water in your aquarium!

Proper filtration maintenance

When it comes to maintaining crystal-clear aquarium water, proper filtration maintenance is key. To ensure that your filtration system is operating at the highest possible efficiency, you should be changing out your filter floss every other week and thoroughly cleaning out your sponges. It’s important not to use tap or RO water when cleaning these items in order to prevent the loss of beneficial bacterial colonies.

It is recommended to regularly clean the piping in power filters and tubing in canister filters. If needed, worn-out mechanical filtration components should be replaced. Chemical filtration media such as chemo-pure can provide added benefits but may be costly to incorporate.

By properly caring for your filters, you’ll be sure to keep your tank water looking crystal clear.

Cycling Your Aquarium

Cycling an aquarium is the first step in resolving cloudy water conditions. To do so, feed your fish less and avoid introducing new specimens until the issue has been resolved. Testing for ammonia and nitrite levels, as well as doing a water change, is recommended to help lower undesired nutrients.

Getting used filter media from a disease-free tank is another great way to jumpstart your cycle process as it will successfully import beneficial bacteria. If you’re looking for a longer-term solution, there are products like Fritz Turbo Start 700 that come in a bottle full of beneficial bacteria and aid the cycle process.

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Finally, installing a UV Sterilizer can help clear murky waters in addition to preventing illnesses and diseases from spreading inside your tank.

Improve The Quality Of Light And Reduce Lighting Times

If you want to improve the quality of light in your aquarium and reduce the haziness that comes with poor lighting, there are a few options available. For example, if you’re using LED lighting, you could invest in an LED fixture that expands to the length of your entire tank – like the Twin Star or Fluval Planted Tank LED fixtures. These fixtures are designed so that any shadows won’t dull out the overall look of your tank.

Alternatively, if you have T5s installed in your aquarium, consider replacing the bulbs. This will brighten up your tank and make it look more vibrant and clearer. Generally speaking, tanks with T5s usually appear to be much clearer than those with LEDs – though higher-end LEDs can be just as effective for creating clear waterscapes.

Lastly, reducing your lighting time is also beneficial when trying to achieve clarity in an aquarium. By minimizing exposure times of lights, you’re also minimizing any potential growth of algae on the glass walls which will leave it looking crystal clear.


Why Is My Aquarium this way?

A new tank may become cloudy or dirty for one of seven common reasons, such as excessive feeding, overcrowding, inadequate filtration, dead fish or organic material in the tank, dirty glass surfaces, or insufficient substrate.

Is Dirty Water Bad For Fish?

Cloudy aquarium water is a sign of an imbalance and can be indicative of a bigger issue. To address it, assess your water quality by testing the aquarium water. Get a baseline of nutrient levels and take measures as necessary. A water change usually helps to restore balance.

How Do I Make My Aquarium Water Crystal Clear?

Proper filtration, maintenance, and stock levels are essential for optimal aquarium water clarity. Equipment like an aquarium UV sterilizer can also help maintain optimal conditions.

Will A Filter Clear Hazy Water?

A filter can improve clouded water. When a tank is new, the filtration system may need time to adjust. Adding another filter may be necessary if the tank has many inhabitants and inadequate filtration for hazy or cloudy water. The filter may also require maintenance if it gets dirty.

Can Driftwood Make My Aquarium Murky?

Driftwood can cause a tank to appear cloudy or murky. It may also release tannins, causing the water to turn a tea-like color. This is not for every looking for, so lower tannin driftwoods like Manzanita or Tigerwood are available for those who prefer to avoid this color.


Understanding why your fish tank gets dirty so quickly is the first step to successfully keeping it clean. Whether it be due to a large bio-load, gravel buildup, or chemical imbalance, taking the proper steps now can make all the difference in the long run.

Doing regular water changes and maintenance can help improve water quality and keep the water healthy for your fish. Don’t forget that prevention is key, so stay on top of regular maintenance and checkups to ensure you have happy and healthy fish!