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. Keep reading to learn our top tips on cleaning fish tanks like a professional.

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 fish tanks need to be cleaned?

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.

Do you take the fish out of the tank when 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. The process of catching them can be more stressful than the slow cleaning.

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

How long do you let water sit before putting fish in?

This old school piece of advice comes from the fact that municipalities often put chlorine in tap water (which is lethal to fish), but if you let the water sit out for 24 hours, the chlorine evaporates. Chloramine, a stable form of chlorine, is used in tap water. 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

We’ve clarified some of the confusion surrounding tank maintenance. Here is a step by step guide that you can follow on a daily basis.

Step 1: Test 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.) These waste compounds can pose a danger to fish if they reach high levels.

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: Get rid of Algae

To keep your fish’s eyes open, use an algae scraper to clean the tank walls. 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.

You can wash the lid off if algae has formed. 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 the plants

If you keep live aquarium plants, take this time to remove any dead leaves and trim down overgrown foliage. To propagate tall stem plants, cut a few inches off their tops and place them back 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. Finally, if the floating plants cover the entire surface of the water, you can remove 30% to 50% to ensure that the fish and plants below have enough light.

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 Equipment

Make sure you turn off all electrical equipment before you remove any 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. As debris can collect under decorations and hardscape, it is important to remove them as soon as possible. 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. For detailed instructions on how to set up a siphon and how to stop it from sucking small fish, please see our gravel vacuum article.

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. Filters are often thought of as a black hole, where fish poop or other waste magically disappears from the water. In reality, filters are more like trash cans that collect waste, but at the end of the day, someone is still responsible for taking out the trash can. Filters also collect fish waste. However, you need to regularly clean them so that any gunk is removed before it gets clogged or overflows.

You can clean a corner box filter with a hang-on back, canister, or canister filter by simply swishing the media in the bucket of water from your tank. (Again, do not use soap, just water.) If you have a spongefilter, remove the foam and run it through a 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. Human hands are able to detect temperatures within one or two degrees, so just adjust the faucet until the tap water feels like it has the same amount of warmth. Empty out the bucket of old tank water (which can be used to feed indoor and outdoor plants), and refill it with tap 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 Equipment

Although you just spent all this time cleaning the tank, it probably looks dirtier than ever with all that particulate clouding up the water. Not to worry – turn on the heater and filter again, and within an hour or so, the debris will settle down or get sucked up by the filter.

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 by spending hours staring at your happy and healthy fish.