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. We will be sharing our top tips to clean your fish tank like an expert.

Before you get started…

There are several frequently answered questions we often hear from beginners, so let’s address those first:

How often do you need to clean a fish tank?

Some people say it once a week while others say it once a month. The real answer is that it totally 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 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. Today, chloramine (a stable version of chlorine) is commonly used in tapwater. It doesn’t 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: Check 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: Get rid of Algae

To keep your fish’s eyes open, use an algae scraper to clean the tank walls. The blade attachment should make it easy to cut through tough 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. (Don’t use soap or it may harm 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. For more information on how to remove algae, see our article.

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 your vallisneria or dwarf sagittaria are spreading into unwanted areas, pull out the little runners and move them elsewhere. 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 your Substrat

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 serves the dual purpose of not only removing fish waste, uneaten food, and dead leaves from the gravel or sand, but also removing old tank water and the excess nitrates in them. 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 allow you to easily change your water without using a pitcher or cup.

Step 6: Clean your filter

You should clean your filter at least once per 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.

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. Again, don’t use soap. Just water. If your sponge filter has foam, take it out and rinse with old tank water. You can read our last section on sponge filters for more information.

Step 7: Fill the water tank

At this point, you can finally refill the tank with fresh, clean water that matches the temperature of the existing aquarium water. Temperatures can be sensed by human hands. Adjust the faucet to ensure that the water is the same temperature. 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 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.