How to Properly Clean Your Fish Tank

When people find out you keep fish, they probably imagine a crusty, algae-coated tank where you can barely see anything swimming inside. 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…

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 once a week, while others say once a month. It all depends on what you do! 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. 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. 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 products do you need?

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)

(As Amazon Associates, we earn commissions from qualifying purchases.

How to Clean Your Aquarium

Now that we’ve cleared up some confusion about tank maintenance, here is a step-by-step guide for you to follow 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.) Higher levels of these waste compounds can be dangerous for fish.

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

In order to maintain a clear view of our fish, scrub the tank walls with an algae scraper. If you have the blade attachment, it should be very easy to slice through any tough algae spots. Just make sure not to catch any substrate underneath the algae scraper, or you may end up scratching the glass or acrylic.

It is possible to rinse off algae from the lid by running water into the sink. Avoid using soap, as it could 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. 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. 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: Switch off the Equipment

Before removing any water, make sure to turn off or unplug all equipment. 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 has two purposes. It removes fish waste, uneaten foods, and leaves from the gravel and sand. It also removes old tank water and 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 allow you to easily change your water without using a pitcher or cup.

Step 6: Clean the Filter

At least once a month, you should clean the filter. Filters are often viewed as a black hole in which fish poop and other debris magically disappear. Filters are actually more like trash cans. However, at the end, it is still your responsibility to empty 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.

The easiest way to maintain a corner box, canister or hang-on-back filter is to simply wash it in a bucket of 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: 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. 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 your opportunity to add liquid fertilizer, root tabs and/or root tars to 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

Even though you spent so much time cleaning out the tank it is probably looking worse than ever because all the particulates are clogging 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: Clean 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!

Get pleasure from the fruits and vegetables of your labor by spending hours gazing at your healthy, happy fish.