How to Properly Clean Your Fish Tank

People often picture a tank with algae and crusty fish when they hear you keep them. But with just a few easy steps, you can keep your aquarium looking like a beautiful work of art. Follow along as we share our top tips for cleaning your fish tank like a pro.

Before You Get Started…

We often get asked a lot of questions from beginners. Let’s start with the most frequently answered:

How often do you need to clean a fish tank?

Some people say it once a week while others say it once a month. It really depends! It all depends on the size of your aquarium, how many fish are kept, and the amount of biological filtration (e.g. beneficial bacteria and live plant) that you have. Fortunately, we have a free guide to help you figure out exactly what frequency is right for your aquarium.

Are you able to take the fish out from the tank for cleaning?

No, go ahead and leave your fish in the aquarium. You won’t be completely draining the aquarium, so there will be plenty of water left for them to swim in. Also, the process of catching them is more stressful for the fish than slowly cleaning around them.

There’s no need to catch the fish before cleaning an aquarium because it will only cause undue stress.

How long can water be left before adding fish to it?

This old-fashioned piece of advice is based on the fact that chlorine can be found in tap water. However, if the water sits for 24 hours the chlorine will evaporate. Nowadays, chloramine (a more stable form of chlorine) is often used in tap water, and it does not evaporate over time. Instead, you need to dose water conditioner to make the water safe for fish, and then you can immediately use the dechlorinated water for your aquarium with no wait time.

What cleaning supplies do you need to get?

If this is your first aquarium, you may need to collect some tank maintenance materials, such as:

Aquarium water test kit – Bucket for holding dirty tank water – Algae scraper (for glass or acrylic) – Algae scraper blade attachment (for glass or acrylic) – Toothbrush for cleaning algae off decor or plants – Scissors for pruning plants – Dechlorinator (also known as water conditioner) Glass cleaner – Towel for wiping up water spills – Glass-cleaning cloth or paper towel – Aquarium siphon (also known as a gravel vacuum)

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How to Clean Your Aquarium

After clearing up any confusion regarding tank maintenance, here’s a step-by–step guide you can use on a regular basis.

Step 1: Assess the water quality

If your aquarium is newly established and has not been cycled yet, you need to test the water to determine if it has 0 ppm ammonia, 0 ppm nitrites, and less than 40 ppm nitrates. (For more info, find out how to cycle your aquarium.) Fish can become sick if they are exposed to higher levels of these compounds.

If your aquarium is already cycled, then the goal is to keep nitrate levels below 40 ppm. To determine the amount of water that should be removed from your aquarium and to determine if you need to take any other steps (based on our guide to water changes), use a water test kit.

A water test kit helps you determine if there are toxic levels of nitrogen waste compounds in the aquarium.

Step 2: Eliminate Algae

An algae scraper is a great way to keep fish in view. If you have the attachment blade, it should be easy to cut through any hard algae spots. Be careful not to catch substrate under the algae scraper or you could scratch the acrylic or glass.

If algae has grown on the lid, you can easily rinse it off in the sink. You should not use soap as it can cause damage to your fish. Finally, if algae covers your aquarium decor, rocks, or plants, try using a clean toothbrush to gently brush it off, either over the sink or in the aquarium. Read our article on how to get rid of algae for more tips and tricks.

Keep algae under control by regularly removing it and balancing the lighting and nutrient levels in your aquarium.

Step 3: Prune your plants

If you keep live aquarium plants, take this time to remove any dead leaves and trim down overgrown foliage. If you have tall stem plants, you can easily propagate them by cutting a few inches off the tops and replanting them into the substrate. If dwarf sagittaria and vallisneria are spreading into unwelcome areas, you can pull out the runners and move them to another area. If floating plants are covering the entire surface of your water, take out 30% to 50% and move them elsewhere. This will ensure that the plants below receive enough light and oxygen, as well as the fish.

Pruning helps plants to focus on delivering nutrients to the healthiest leaves, and it also allows light to reach leaves at the bottom of the stems.

Step 4: Turn off the equipment

Turn off and unplug any equipment before removing water. Aquarium heaters and filters are not meant to operate without water and therefore can become damaged when running in dry air.

Step 5: Vacuum the Substrate

Take out your nifty aquarium siphon and vacuum approximately one-third of the substrate. Move any decorations or hardscape as needed, since debris tends to collect underneath them. The siphon is used to remove fish waste, uneaten food, leaves, and other debris from the gravel or the sand. Additionally, it can also be used to drain old tank water as well as excess nitrates. You can find detailed instructions for how to start a gravel vacuum and how to stop it if you have accidentally taken in a small fish.

Siphons are one of the most useful tools for easily changing water without having to use a cup or pitcher.

Step 6: Clean the filter

The filter should be cleaned at least once a month. Many beginners think of filters like a black hole where fish poop and detritus magically disappear from the water. Filters are actually more like trash cans. However, at the end, it is still your responsibility to empty the trash can. Filters collect fish waste in the same manner, but you still need to clean them regularly so that the gunk doesn’t build up.

If you have a hang-on-back, canister, or corner box filter, the easiest way to maintenance it is to swish around and wash the filter media in your bucket of recently removed tank water. You should not use soap. Use only water. If you have a sponge filter, remove the foam portion and wring it multiple times in the bucket of old tank water. For more details, read the last section of our sponge filter article.

Step 7: Refill the Water

At this point, you can finally refill the tank with fresh, clean water that matches the temperature of the existing aquarium water. The human hand can sense temperature within one to two degrees. Simply adjust the faucet until you feel the same warmth. You can empty the bucket of tank water, which can be used for indoor and outdoor plants, and then refill it with water. You can either add dechlorinator into the bucket (dosed based on the bucket’s volume) or directly into the tank (dosed based on the aquarium’s volume). This is also your chance to add liquid fertilizer and/or root tabs for the substrate.

If you’re worried about messing up your aquascape or substrate, pour the new water into the aquarium through a colander or onto another solid surface (like your hand or a plastic bag) to lessen any disturbances.

Step 8: Turn on the Equipment

Despite all the effort you put into cleaning the tank, the water is likely to look even worse because of all the particulate that has built up. Don’t worry, just turn on the heater again and the filter will work overtime to remove the particulate.

Step 9: Wipe the Glass

For that extra, crystal-clear finish, wipe down the outside walls of the tank with aquarium-safe glass and acrylic cleaner to remove any water spots and smudges. Also, clean off the dust that has collected on the lid, light, and aquarium stand. Now you have a truly Instagram-worthy aquarium ready to wow your friends and family!

Enjoy the fruits of your labor and spend hours looking at your happy, healthy fish.