How to Clean a Fish Tank – A Complete Guide (EASY)

Keeping your fish tank clean is one of the most important parts of caring for fish. You need to know how to do it properly before you purchase your pet.

The cleanliness of your tank and water affect how healthy your fish can be. Dirty tanks can lead to sick fish, so regular maintenance is essential. However, cleaning your tank incorrectly can also cause problems for your fish.

Use this article as a comprehensive guide on cleaning your fish tank. Refer back to it if you have any questions about tank maintenance and for answers to common questions.


Why Do You Need to Clean Your Tank?

Hygiene is important for every living thing, and fish are no exception. Fish need to be kept in clean, healthy environments to avoid getting sick.

Dirty tanks can cause illnesses for several reasons. Here are four reasons why you should clean your tank regularly.

Tank Cleaning Removes Food and Waste Particles

Fish eat food and produce waste just like we do. It’s important to remove these particles frequently so fish don’t have to live in dirty water.

An important part of feeding your fish is removing excess food from the tank after they’ve eaten. Most filters can’t remove it from the water, so you need to do it yourself.

Leaving flakes, pellets, or live foods can lead to dirty water from the spoiled food. Your fish can also overfeed, which leads to health problems like fatty liver, improper digestion, and even fish rot.

Waste and other organic matter that your fish produce can also fail to pass through your water filter. Water needs to be changed out periodically to remove these particles.

Tank Cleaning Removes Nitrites

All fish are subject to the nitrogen cycle, in which ammonia is changed into nitrites and nitrates that are toxic to fish. The good, healthy bacteria in your tank that do this are necessary, but you need to clean your tank regularly to monitor nitrite levels.

Ammonia and nitrite are the most dangerous chemicals produced by the nitrogen cycle. Nitrates are less toxic, but high levels should be avoided.

Cycling your tank before filling it with fish is one way to avoid high nitrite and ammonia levels, but it cannot prevent them. Regular tank cleanings can help keep them low, but you should monitor your water’s nitrite levels frequently.

Tank Cleaning Prevents Rotted Plants and Decorations

Fish aren’t the only things that live in your tank. Most tanks also have decorations like live plants, substrate, and other ornaments to make the tank more interesting to look at.

High ammonia and nitrate levels in your tank’s water can kill common aquarium plants. Keeping these levels low protects your decorations as well as your fish.

Rotted plants are easy to spot. They will usually turn a black or brown color, become slimy, and smell bad. The smell might stick around your tank, so you might need to clean your tank after you remove the rotten plant.

Tank Cleaning Maintains Minerals and Healthy Bacteria

It may not seem like a good idea to keep bacteria in your tank, but there are some bacteria that keep your fish healthy. Bacteria are necessary to perform the nitrogen cycle and remove the ammonia from your tank.

Not cleaning your tank can lead to an increase or decrease in these bacteria. You want enough in your tank to maintain low ammonia levels, but too many will create too much nitrite that can harm your fish.

Your tank’s water also needs to have high levels of minerals your fish need. Magnesium and calcium keep your fish healthy, but these mineral levels can drop if you don’t clean your tank often.

Tank Cleaning Supplies You Need

Research every tool or cleaning supply on this list before you purchase it. Some cleaning supplies can contain harmful chemicals. Make sure everything you use is aquarium safe.

Algae scrapers and pads can be found in the housewares department of your local grocery store. However, you should only purchase algae scrapers from your local pet store. This is to make sure they are free of chemicals or soaps.

Bleach is a great way to clean your tank, but you need to be extremely careful when using it. Some bleaches have high levels of chlorine or have been mixed with detergent. Only buy regular bleach that’s safe to be used in your aquarium.

If you use bleach in your tank, dilute it before cleaning with it. Mix nine parts of water with one part of bleach. Even the right bleach can hurt your fish if you use too much of it.

You will need a bucket to replace the water in your tank while cleaning. Use a new bucket that is dedicated for aquarium use only.

Filter media needs to be replaced every two to three weeks if you use it. Different water filters use different media. Purchase the type recommended by your filter’s manual.

A filter brush is also useful for cleaning your water filter. It can reach into your filter’s tubing and remove any debris and waste that might be there.

Gravel vacuums help you clean your tank’s substrate. These are also called water siphons, but both will work for cleaning your substrate.

You will need a way to remove lime from your tank, the white residue that can build up because of hard water. There are glass cleaning sprays available in pet stores, but white vinegar is also effective.

A razor blade can help with stubborn residue on your tank’s glass. If you have an acrylic tank, use a plastic razor blade to protect the acrylic.

You’ll need multiple kinds of towels when cleaning your tank. Stock up on paper towels, small wash cloths, and large bath towels.

Water conditioners remove chlorine from your water and maintain healthy water hardness and mineral levels. You should condition your tank’s water regularly, and always when you refresh your water.

When Do You Need to Clean Your Tank?

You need to clean your tank regularly, but it’s hard to figure out how often you need to clean. Keep an eye on the signs that tell you need to clean. You should also clean your tank before adding any fish to it.

Signs You Need to Clean Your Tank

One obvious sign you need to clean your tank is that your fish are getting sick or even dying. Most fish illnesses begin due to something wrong with your tank’s water. It might not be because it’s dirty, but it’s a sign you need to investigate.

Fish that gasp at the water’s surface are trying to get more oxygen, and they might need it for a few reasons, including water that’s too warm or dirty water. Clean your tank or lower your water’s temperature to fix this problem.

Other changes in your fish’s behavior is a warning sign. Research the behaviors they’re exhibiting and clean your tank to try to fix them.

If your water changes color, you definitely need to clean your tank. Water becomes white and cloudy when the gravel and substrate aren’t properly washed or bacterial bloom.

Water can also turn green and murky if you leave food particles in your water. This buildup of organic waste can also lead to fuzzy substrate and worms in your tank.

Rotten plants and decorations can also point to a dirty tank. These decorations can deteriorate for any number of reasons, but this can also be a sign that you need to clean your tank.

How Often Should You Clean Your Fish Tank?

Everyone says you should clean your tank regularly, but how often do they mean by that? The truth is that you need to complete different cleaning tasks at different times.

You do not need to clean your tank every day. Still, you should monitor how clean your tank is on a daily basis to look for signs that your fish are unwell.

Most cleaning tasks should be done every week or two. Different types of water and fish need different types of maintenance, so research how often you need to clean and refresh your water based on your tank.

Your tank equipment should also be cleaned on a regular basis. Research your filter and other equipment and follow their instructions, but every month or two is best.

You should deep clean your tank about twice a year. You don’t need to empty your tank to do this. Only remove your fish for tank cleaning if it’s absolutely necessary.

Even with these guidelines, your tank’s cleaning needs will depend on a few factors. How large it is, whether you have saltwater or freshwater, and how many plants and animals you keep will change how often you need to clean.

Cleaning Your Tank Before Adding Fish

It’s clear that you need to clean your tank regularly once you’re housing your fish. But did you know that you need to wash it before you add fish to it?

After you purchase your tank, you will need to clean it and the decorations you add before adding any fish. This will clean the glass of any harmful chemicals used during the manufacturing process.

Use warm water to rinse the inside and outside of the tank and pat dry with a paper towel or wash cloth. Only use warm water without any other soaps or detergents added.

Next, clean the substrate and gravel you’re going to add to the bottom of the tank. Rinse your substrate in warm water and a colander or sieve until the water runs clear. Add the substrate carefully to avoid scratching the glass.

Fill your tank a third of the way full after adding the gravel and substrate. Now’s the time to add your water conditioner.

Once you’ve finished setting up your tank, you will need to cycle it before adding fish. This will help the healthy bacteria you need to build up in your water.

Daily and Weekly Fish Tank Maintenance

You don’t need to clean your tank every day, but look for signs every day that you might need to clean. This will help you keep your fish healthy and your equipment in good shape.

When you feed your fish, take the time to look at how all your fish are behaving. If they’re sick, you might need to clean your tank or your water.

You should also check your water’s temperature every day. This isn’t necessarily connected to cleaning your tank, but it is a maintenance task that should be on your checklist every day.

There are additional tasks you should complete once a week. Look over your equipment to make sure your lights and water filter are working properly.

Use your algae scraper to clean your tank’s glass once a week. This will prevent harmful bacteria and build up on the sides of your tank. If there are any stubborn pieces, use a razor blade to scrape them off.

Also check your water’s pH and nitrite levels once a week. If these levels are imbalanced or too high, you should change your tank’s water or clean soon.

How to Change Your Tank’s Water

Changing your tank’s water is the main cleaning task you’ll have on a regular basis. It’s an important chore because keeping your fish in the same water can cause disease.

Every tank is different and require water changes at different times. Start by changing your water every two to three weeks if you’re unsure.

The amount of water you need to replace also depends on your tank. Replacing too much water at once will shock your fish, but not refreshing enough will keep harmful materials in the tank.

Different sources on how much water to change at once range from 10% all the way to 30%. It’s best to start small at 10-15%. Still, research your fish and your tank to figure out how much you should refresh and how often.

Wash and dry your hands thoroughly before changing your tank’s water. Any traces of soap or other materials can harm your fish.

You should be scraping any algae out of your tank once a week. Check for algae and scrape it out of the tank before you begin removing any water.

Use your water siphon to remove water from the tank. Do this slowly to avoid startling your fish.

It’s easiest to remove the water by submerging the siphon into the tank and using your thumb to create pressure in the tube. Then, move the siphon to a bucket and move your thumb to release the water.

You can also use your gravel vacuum to remove the water. This will not only change the water in your tank, but it will also enable you to get rid of waste in your substrate at the same time.

Have a bucket reserved only for adding new water to your tank. Bring it to temperature and condition it before adding it to the tank so it doesn’t change your tank’s conditions and harm your fish.

Add the new water by slowly pouring it into the tank. You can also use your water siphon to move water from the bucket to the tank using the same method you used to remove the old water.

How to Clean Your Tank’s Water Filter

There are many different kinds of water filters. Each type needs to be cleaned at different rates. Follow the manual you received when you purchased your filter or use this section as a general guide.

Whenever you clean your water filter, rinse it using water from your tank. Tap water can introduce chlorine or unhealthy minerals to your filter, which is meant to keep these chemicals out.

You should also schedule your filter cleanings at different times than your water changes. Removing too much water from your tank at once can harm your fish.

There are already healthy bacteria in your tank that help with filtering your water. Biological filters are another place in your tank these bacteria can process the nitrogen cycle and remove waste.

Biological filters also don’t require as much cleaning as other filter types. Rinse it in tank water once a month and scrub it with a filter cleaning brush.

Chemical filters use filter media to remove nitrite and waste from your tank. Carbon media is the most common.

You should replace your filter’s chemical media whenever your tank’s water turns cloudy. Replace the media if it has been longer than two months since you last changed it.

Mechanical filters require the most maintenance to keep your water clean. These filters use a media like a sponge or pad to filter tank water through. Rinse your mechanical filter media in tank water once a month.

Replace your mechanical filter media when it begins to fall apart. Keep the old media in the filter along with the new sponge or pad to help the new media build up healthy bacteria.

The main filter, the place that holds whatever filter media you use, does not need to be replaced unless it is faulty or broken. You should still rinse the main filter and clean the tubing with tank water about once a month.

Common Fish Tank Cleaning Questions

We’ve covered a lot of useful information, but you might still have questions about how to clean your fish tank. Here are the most frequently asked questions about tank cleaning.

Should I Remove My Fish from the Tank When I Clean?

Do not move your fish from your tank unless it is extremely dirty because the move will stress your fish. You should only move them if your tank water is making your fish sick.

It can be most tempting to remove your fish if you have a small bowl or tank. Instead, perform small water changes more often to keep the water clean.

If you have to move your fish, move them to a tank that is filled with the original tank’s water or water kept at the same conditions. This will help reduce the stress your fish will experience.

Why Can’t I Refresh My Water and Clean My Filter at the Same Time?

Changing your water is beneficial because it maintains healthy pH, nitrite, and hardness levels in your tank. However, it disrupts the healthy bacteria in your tank that perform the nitrogen cycle and filter your water.

A lot of the bacteria that keep your tank healthy live in the filter. It’s important to leave it alone for about a week after you change your tank’s water.

When you change your water and your filter at the same time, you risk triggering an ammonia spike in your tank. This leads to unhealthy amounts of nitrite and nitrate that can hurt or kill your fish.

To avoid this, alternate and space out your water changes and filter media changes. This will maintain healthy bacteria levels in your tank.

My Tank Has Eggs in It. How Do I Clean It?

Most fish fries hatch about a week after the parents lay their eggs. The eggs should not interrupt your cleaning schedule, but you can delay your cleaning by a few days until the eggs hatch.

If you must clean your tank while there are eggs, use your gravel vacuum in the substrate but avoid the areas where the eggs are buried. Never clean a tank with eggs at the surface of the water or the sides of the tank.

Cleaning Summary

Every tank’s cleaning requirements are different, as they depend on the type of water in your tank, how large the tank is, and how many plants and animals live inside. However, there are a few key cleaning tasks that all tanks need.

Refreshing your tank’s water on a regular basis is the most important cleaning task you can perform. Scrape algae off the sides of the tank when you do this as well.

Space your water changes out and alternate them with cleaning your filter and replacing your filter media. Different filters have different maintenance schedules. Never clean your filter at the same time as you change your water.

If you follow through with these cleaning tasks regularly, you will not need to “deep clean” your tank. Regular maintenance creates a healthy, clean tank for your fish.

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