The least exciting part of owning an aquarium is dealing with routine maintenance. But knowing how to clean a fish tank or fish tank will save you time and money in the long run. A tank in good condition is usually a healthier one that suffers from fewer problems.
It’s a lot easier to clean your tank than you think, and you don’t need any special skills or expensive equipment either. In this DIY tutorial I will show you step by step how to clean an active aquarium of any size.
FREQUENTLY ASKED QUESTIONS ABOUT CLEANING THE AQUARIUM
Before we dive into the details and throw out lists of the equipment you’ll need, let’s take a second to discuss why routine cleaning is so important to the health of your tank and the species it contains.
WHY DO WE CLEAN AQUARIUMS?
The most important step in your tank maintenance routine is regular water changes. Since an aquarium is a closed system, fish waste and other debris accumulate in the water. If you don’t remove and replace some of the water in your tank at regular intervals, this waste breaks down and poisons your tank.
A filter can help remove physical waste and neutralize toxins to some extent. But they can only give you more time between water changes, and they don’t replace regular maintenance. You’ll still need to keep up with algae removal, maintain your filter, and know how to clean fish tank gravel.
WHAT DOES IT MEAN TO CLEAN AN AQUARIUM?
Cleaning is quite a broad term and encompasses many different tasks when it comes to maintaining an aquarium. I tend to talk about specific actions, like doing a water change or vacuuming gravel using the term “clean”. When you clean your aquarium, you will do at least a partial water change.
Depending on your tank conditions, you may also need to change the filter pad and/or filter media, vacuum gravel, or remove algae growing on the sides or decoration of the tank. But don’t take cleaning too far. In fact, you can make a tank crash like a new tank if you clean it too thoroughly!
You’ll also want to clean exterior surfaces. Once a month, you’ll want to polish your glass or plastic tank and dust off the aquarium hood, light fixtures, and any pipes or equipment wires that are in your setup.
HOW OFTEN SHOULD YOU CLEAN YOUR TANK?
Unfortunately, there are many variables involved. I can’t give you a hard and fast answer. You will need to come up with a schedule for your tank based on its unique characteristics.
The frequency of water changes and aquarium cleaning depend on:
- The size of your tank and the type and density of inhabitants.
- If you are using a filtration system and what type of filter you have
- The location of your setup and the amount of light the tank receives
In general, you will need to do water changes and clean your tank at least once a month for larger setups and up to several times a week for smaller setups. Here are some guidelines:
| tank size | Filtration system? | Quantity and frequency of water change |
Other cleaning and maintenance |
| Fish tank less than 5 gallons | Nope | 10% to 50% change2 to 3 times a week | As neededWeekly or bi-weekly |
| Fish tank less than 5 gallons | Yes | 10% to 30% change1 to 2 times per week | As neededWeekly or bi-weekly |
| 5 to 10 gallons | No (not recommended) | 10% to 50% change3 to 4 times a month | As needed1 to 2 times a month |
| 5 to 10 gallons | Yes | 10% to 30% change1 to 3 times a month | As needed1 to 2 times a month |
| More than 10 gallons | No (not recommended) | 10% to 30% change1 to 2 times a month | As neededOnce a month |
| More than 10 gallons | Yes | 10% to 30% change1 to 2 times a month | As neededOnce a month |
HOW MUCH WATER TO CHANGE FOR A ROUTINE WATER CHANGE?
Routine water changes usually involve removing and replacing a small percentage of the water in your tank. 10% – 25% is a typical amount to replace, but if your aquarium is especially dirty, a 30% to 50% change may be necessary. I do not recommend changing more than 50% every 24 hours to avoid stressing the fish.
If you’re having trouble with a foggy fish tank or an extreme algae or cyanobacteria outbreak that doesn’t improve with routine water changes, you’ll want to evaluate your equipment and water quality, and possibly seek professional advice.
DO YOU HAVE TO REMOVE FISH TO CLEAN A TANK?
No, you don’t have to take the fish out of the tank to clean it! If you have a very small fish tank, it may help to put the fish in another container to clean it, but I’ll show you an even easier method below. For larger tanks over 5 gallons, you don’t need to worry about removing them. You will clean around them instead!
How to clean rocks and aquarium decoration?
Occasionally, you may find it easier to take out an algae-encrusted rock or decoration and scrub it with a pad and plain water. However, if this is an ongoing problem, you should consider adding algae-eating aquarium species like snails or freshwater shrimp, or reducing the amount of light your tank receives.
SPECIAL CONSIDERATIONS
This tutorial is primarily aimed at fish keepers with existing freshwater setups rather than those installing new tanks, tanks with problems, or maintaining 500 gallon saltwater reef tanks. I recommend looking for detailed advice for your particular situation, but I’ll touch on it briefly here.
NEW AQUARIUMS
New setups can be a bit frustrating as it takes time for the aquarium substrate to settle and the tank to function to avoid “new tank syndrome”. This is a whole topic in itself.
You shouldn’t add fish to a new tank right away, although the amount of time you’ll need to wait depends on the size of the tank, the type of substrate, and the heating and filtration systems. It takes time for healthy aquarium bacteria to establish itself in your tank and you may need to do additional water changes as well.
I recommend waiting at least a few days and then gradually adding new fish over the course of a month rather than adding many fish at once.
HOW TO KILL ALGAE IN AQUARIUMS
Most tanks will eventually see algae growth. The algae take advantage of the light and nutrients from the fish waste to spread. Regular water changes should keep its growth in check, so you don’t have to work to eliminate it completely.
If you have aquatic species that feed on algae, you will need some algae to feed them. If you have a problem with algae that the water changes and the algae eaters can’t control, try moving the tank out of direct sunlight and reduce the amount of light it receives.
You can also manually remove algae from the sides of your tank with a special glass or plastic scouring pad or magnetic aquarium scraper.I keep them on hand to remove excess algae from my tank during my monthly maintenance routine.
HOW TO CLEAN A PLASTIC FISHBOWL
Aquariums are usually made of glass, plexiglass, or plastic. Make sure any gravel scrubber or vacuum you have is safe with your type of tank. This isn’t really a problem with gravel vacs as they are usually plastic. But a scrubber made for a glass tank could scratch a plastic aquarium, so be careful.
Aside from trying to prevent scratches on your tank, cleaning a plastic tank is like cleaning a glass one.Never use bleach, soap or other cleaners on any type of aquarium or decoration, plastic or glass. Plastics and silicone sealant used in glass tanks can absorb the cleaner and release it into the water, which can be toxic.
HARD WATER AQUARIUMS AND SALTWATER FISH TANKS
In most cases, changing the water in a saltwater tank is similar to a freshwater setup. You will use the same equipment to remove and replace the water. But it will also monitor salinity levels in a saltwater aquarium and deal with something called salt carryover.
Salt carryover occurs when water evaporates from your saltwater tank. As water splashes out of your cooler or filter, it creates a salt mist that can dry out and foul your gear. If not removed regularly, salt will build up and corrode or damage your light fixtures and other equipment.
This problem is also common in freshwater aquariums in areas with very hard water. The minerals in the water act much like salt and form a crust on your tank and equipment. You have to gently scrape off any salt or minerals while doing your regular maintenance routine.
EQUIPMENT NEEDED TO CLEAN AN AQUARIUM
There are many kits available online to clean an aquarium, but what do you really need? You can even use vinegar to clean. The equipment needed depends on the size of your setup. I have divided my lists into 3 categories based on the size of the aquarium you are cleaning.
While you can certainly use the list and instructions I recommend for one size tank on another, it may not be ideal. Trying to swap out a 10 gallon tank of water using my method for a fish tank would take forever!
CLEAN A FISH TANK OR TANK LESS THAN 5 GALLON
What do you need to regularly change the water and clean a small fish tank? Turns out not much. These small bowls are usually easy to lift and move, so you can change the water right next to your kitchen or bathroom sink.
I have included two different techniques for cleaning fish tanks because my preferred method (the second technique) does not work with extremely small tanks. For those, you’ll want to use the first list and method as described below.
Equipment Needed: First Fish Tank Cleaning Technique
If you have an extremely small setup, like a half-gallon betta bowl (not recommended), you may find it easier to move the fish and half of the water to another bowl before cleaning. In that case, you will need:
- A specific glass or plastic container large enough to hold your fish and about half of the water in your tank. If you opt for a plastic container, use it only for fish and never clean it in a dishwasher or with soap, bleach, or other chemicals.
- A small fishing net to catch and transfer your pets from one container to another.
- appropriate water conditionerto neutralize chlorine, chloramine and other chemicals in tap or aquarium water (such as ammonia).
- Small scrubbing pad to remove algae or hard water deposits.
- Optional: A new turkey baster, for fish only, never washed with soap, bleach, or chemicals.
Equipment Needed: Second Fish Tank Cleaning Technique
For this second technique, you will leave your fish in the original container and clean around it. You will need to:
- A cup or small scoop to transfer water from the tank to the sink. An inexpensive turkey baster used just for routine cleaning can also work and is very helpful in picking up physical debris from the bottom of the container without risk of harming the fish.
- appropriate water conditioner.
- Small scrubbing pad.
- Optional: If you can’t get your bowl to a sink, use a dedicated glass or plastic container to transfer water between the bowl and the sink.
CLEANING A SMALL 5-10 GALLON TANK
While you can move a small fish tank, it is much more difficult to move a small aquarium. A 5 gallon tank can easily exceed 60 pounds in weight once you account for substrate and water. To change the water in these settings, you’ll need a bit more equipment:
- A simple gravity-based siphon and hose with a gravel suction tip.
- A special bucket that is used only for aquarium maintenance and is never cleaned with bleach, soap, or other chemicals. Choose one with a comfortable handle and convenient pouring spout that holds 3 to 5 gallons.
- suitable water conditioner.
- Aquarium-friendly scrubbing pad sized to fit your aquarium.
CLEANING A LARGE TANK OVER 10 GALLONS
The gravity bucket and siphon method works great for tanks up to 10 gallons in size. But I doubt anyone would want to carry 25 gallons of water or more in buckets! Instead, for larger aquariums, I recommend investing in a vacuum system that moves water in and out using water pressure from a nearby faucet.
You’ll need enough hose to get between the sink and the aquarium, but you won’t have to move buckets. These devices can be difficult to understand at first because you may need to customize the settings to make it work with your faucet. To clean a large tank you will need:
- Faucet attachable adapter with enough hose to reach your aquarium and a gravel vac tip on the end. These are often called no-spill or motorized gravel vacuum systems.
- suitable water conditioner.
- Algae scrubber suitable for aquariums.
STEP BY STEP INSTRUCTIONS: HOW TO CLEAN AN AQUARIUM
All you have to do is choose the method that works best for your tank based on its size and follow the instructions! While you can use any of these methods to clean aquariums of any size, I’ve tailored each technique to the amount of water you’ll be playing with.
HOW TO CLEAN A FISH TANK: FIRST TECHNIQUE
If your tank is very small or has a narrow opening, you may not have enough room to fit a cup or scoop inside to scoop the water out of the tank. Instead, you’ll use another container to hold your fish and some of its water while you clean the container.
Always remove filtration systems and unplug heaters you are using before cleaning a tank. Your heater may also take a few minutes to cool down, so be careful and have a safe place to put it while you clean.
Step 1: Move the bowl and place it next to your kitchen or bathroom sink
Carefully move your filled fish tank and place it on the counter next to the sink. Get out your gear and get ready to start cleaning! Alternatively, if it is not convenient to move the container while it is full of water, you can skip this step and go to Step 2.
Don’t forget to clean the lid or hood of the bowl with a damp rag and scrape off the stubborn stuff with the scraper.
Step 2 – Transfer the Water from the Fish Tank to the Temporary Fish Tank
Carefully pour some of the water from the tank into your temporary container, or use the turkey baster to move the water from one to another. Be careful not to spill your fish with the water, as this could cause injury or stress to your pet.
You will need to take out at least a cup of water so that your fish have enough to swim in while you clean the tank.
Step 3 – Transfer Your Fish to the Temporary Container
Using the fishing net, catch your fish and gently transfer them to the temporary setting. Once you do, examine your tank and see if the decorations or the sides of the tank need to be scrubbed as well. If so, you can gently clean the algae with a scouring pad now.
Step 4: Place the fish tank in the sink under the faucet
Gradually turn on the water until it pours into your container with enough force to stir up the substrate a bit. You don’t want to upset the substrate completely or destroy any good bacteria that live in it. You want enough water to get in to lift the debris off the top of the substrate and up the side of the container.
Let the water flow for a minute or two, until visible debris from the top of the substrate has been removed.
Step 5 – Adjust the Water Temperature and Refill Your Fish Tank
Once your bowl is clean enough (and for multi-week cleanups you don’t need to have a perfectly clean bowl) adjust the water temperature to match the temperature of the water in your temporary bowl. Let the tank refill, leaving room for the water and fish in the temporary tank.
Step 6 – Add the Proper Amount of Water Conditioner
Once your tank is clean and refilled, follow the instructions for your brand of water conditioner and add the correct amount to the water in the tank. If you partially emptied your tank before moving it to the sink, return it to its original location before adding the water and fish back in.
Step 7: Return Fish and Water to Bowl
Using your fishing net, gently catch your fish and transfer them back to your fish tank. You can carefully pour the water from the temporary container into the tank or transfer it with the turkey baster, being careful not to disturb the substrate or decorations. Return the tank to its usual location and voila!
HOW TO CLEAN FISH BOWLS: SECOND TECHNIQUE
For wider or larger fish bowls, you should have no problem fitting a Styrofoam cup, soup ladle, or even a turkey baster inside. With this method, it may be easier to leave the tank in place and use another dedicated container to carry wastewater to the sink and bring in fresh tap water.
If you’re not moving your fish tank, you can leave the filtration system in place, but you still need to unplug and remove the heater. This will give you more room to fit a cup or ladle inside and will eliminate the risk of accidentally knocking over and breaking your warmer.
Step 1: Transfer the water from the fish tank to the transfer container
Give the substrate a little stir to lift debris from the bottom of the container, and move the decorations if there is a lot of material hidden under them. Place a cup or bucket in the tank and scoop out some of the dirty water. Be careful not to catch your fish too!
You can remove a little water or up to half of the container if it is very dirty. If there is a lot of debris in your bowl, consider targeting it with the turkey baster instead of just scooping up water. Pour residual water into your transfer container as you clean.
Step 2 – Check the sides of your bowl and decorations for excess algae
If you need to remove the algae, use a suitable scourer to clean them from the container or its decoration. A little algae in a fish tank is not a concern, but if you don’t have an algae eater, you may want to be on top of it a bit more so it doesn’t get out of hand.
Don’t forget to clean the lid/hood of your bowl with a damp rag and wipe down the parts that need it. You can do it in a sink if that’s easier.
Step 3: Empty the residual water and adjust the temperature of the tap water
Pour the dirty water into a sink (or use it for your houseplants or garden!). Turn on the faucet and adjust the temperature until it matches the water already in your fish tank. Rinse out the temporary container and refill it with warm tap water.
Step 4 – Add the Proper Amount of Water Conditioner
Following the directions on your bottle, condition the water in the transfer container and return to your tank. Carefully pour in the water or gently transfer it with the turkey baster. Try not to disturb your substrate too much. Replace the heater in the tank and plug it in, and turn the filter back on as well. You’re done!
HOW TO CLEAN SMALL AQUARIUMS
While you can take your fish tank directly to the sink, for tanks larger than 5 gallons, you’ll need to use a bucket to move the water back and forth. You will also have to get your hands into your aquarium. You can also go with the method I use for larger tanks, but it might be overkill for a small 5 gallon setup.
I recommend washing your hands and arms with hot, soapy water and rinsing them well before you begin. This will remove any oils and bacteria from your skin, along with any lotions, perfumes, or other things that could contaminate your tank. I do this every time I need to reach into my aquarium, and it’s a good habit.
Step 1 – Examine Your Tank, Remove Algae, and Prune Plants
Prepare all your equipment before you start. Examine your tank and equipment to see what additional cleaning you will need to do. Remove lid and turn off filtration system and heaters. If your tank is fairly small, you may want to remove the heater while you clean, but that’s optional.
Use a scouring pad or magnetic glass cleaner to remove excess algae from the side of your tank. You can also remove plastic plants or rocks and decorations, if necessary. It’s best to simply remove the leaves from live plants that are covered in algae. You can also prune your plants for healthier growth.
Step 2 – Place the Siphon and Bucket Next to the Aquarium
Place the siphon or gravel vac into your aquarium with one hand. Point the end of the hose toward your bucket with your other hand. Prime the siphon as directed and the water should move by gravity from your tank to the bucket. It’s also helpful to have a clean towel nearby to dry your hands.
Step 3: How to Clean Fish Tank Gravel While Changing the Water
As the water is poured into the bucket, use the tip of the gravel vacuum to carefully remove debris from the substrate in your tank. You will see the dirty water flowing through the siphon. Focus on the areas around plants and decorations, as this is where most of the debris is likely to be hiding.
Try to avoid picking up your substrate along with the debris. This is usually more of a problem with light sand than gravel or rocks. Also, be careful not to accidentally pick up your fish or invertebrates!
Step 4: Empty the residual water
Once your bucket is full, stop the flow of water so you can empty it. Some siphons have a switch to close the line so you don’t have to break the suction. You can always remove the siphon and vacuum nozzle from the water to stop the flow, but you’ll have to prime it again to restart the flow.
You may need to make several trips to flush the dirty water out of your tank. It just depends on how much water you are changing and the size of your bucket. Your goal is to remove about 10% to 30% of the water in your tank and you don’t have to be precise.
Step 5 – Adjust the Water Temperature
Before you can start filling buckets of water to refill your tank, you’ll need to adjust the temperature to match that of the water in your tank. I find that it is easier to add the correct amount of water conditioner to the tank just before starting to fill it, rather than conditioning each bucket individually.
Step 6 – Fill Your Tank
Using the warm water from your faucet, refill your bucket and take it back to your tank. Gently pour the water into the tank, trying not to disturb the substrate too much. You can place a small ceramic plate in the tank to disperse the water if you prefer. Once your tank is full, remove the plate and reset the filter and heater.
Step 7. Clean the hood and light fixtures
Don’t forget to clean your tank lid/hood with a damp rag and scrub any parts that need it. You can do it in a sink if that’s easier. Be careful if your lids are glass and place them on sponges so you don’t accidentally break them.
Using the dry towel, wipe any spilled water off the sides of your tank. Replace the hood or cap. That’s all you need to do until your next water change!
HOW TO CLEAN LARGE AQUARIUMS
The main difference between cleaning a small aquarium and a larger one is the way you transfer the water. It’s just not very practical to use buckets for larger capacity tanks. Instead of using a gravity siphon, invest in a gravel vac that attaches to your kitchen sink. Still, you should first thoroughly wash your hands and arms.
These “no spill” systems use a special faucet adapter and hose system. The pressure of the water coming out of the faucet creates suction in the hose. When you put the tip of the gravel vac into the tank, it will pull the water out and send it down the sink drain. No buckets and less mess!
Step 1: How to remove algae from fish tanks
As with smaller tanks, you should have all of your equipment ready before you begin. Examine your tank and look for algae to clean. Remove lid and turn off filtration system and heaters. You shouldn’t need to remove the heater, but be aware of its location so you don’t accidentally break it.
Use a scouring pad or magnetic window cleaner to remove excess algae from the sides of the tank. You can remove plastic plants or rocks and remove leaves from live plants that are covered in algae.
Step 2: Set up your faucet adapter and gravel vac
Plug in your gravel vac and test the adapter both open and closed before you begin. You don’t want to find out halfway through that you need to make adjustments, because this could send water all over your countertops. Attach the tip of the gravel vac to your tank and secure it with a clip.
Go back to your sink and turn on the faucet, leaving the adapter open so the water goes into your sink and down the drain. You should quickly see water running down your empty aquarium hose. Once you’re sure it’s working, return to your aquarium.
Step 3: Vacuum the gravel while removing the water
Similar to Step 3 for smaller aquariums, move the gravel vacuum tip through the top layer of your substrate and around your plants and decorations. Pick up as much visible debris as you can without grabbing your fish or other tank occupants. Focus on getting the water out of the bottom parts of the tank.
Once you’ve removed the percentage of water you want, close the valve on the hose near the tip of the vacuum and attach it to the side of your tank. Head back to your sink for the next step.
Step 4 – Adjust the Water Temperature
Back at your sink, adjust the temperature until the water coming out of the faucet is the same as the water in your tank. Once you’re ready, close the adapter so this hotter water goes into the
