I am often amazed at how many people approach cleaning a fish tank much in the same way they change a cat’s litter box or wash the dog.
From changing the water too often to improper filter care, the mistakes you make will cost fish and other tank inhabitants their lives and well being.
Over time, these are the cleaning schedules, methods, steps, and tools that I found work best.
How Often Should You Clean Your Fish Tank?
Every freshwater tank is a little bit different in terms of the water chemistry, inhabitant population, and owner’s habits. As a result, it is impossible to create a viable aquarium cleaning schedule that will apply to every aquarium.
I have kept some tanks where I don’t clean them for months on end, and others that required more maintenance.
In general, the more I learned about good aquatic habitats, proper feeding, and light management, the less I needed to do anything more than top off water lost through evaporation.
It is, perhaps, better to ask “How often should I check water chemistry?”
This is actually quite easy to answer from a universal perspective. You should check tanks operating under 1 year old at least once a week.
After that, you can extend that time frame to every 2 weeks as long as:
- The pH, hardness, and nitrate levels are stable
- Ammonia and nitrites remain at zero
- The fish and other inhabitants appear to be in good condition and healthy
Depending on the results of the water chemistry tests, you may or may not need to use one or more of the six methods for cleaning a tank presented in this article.
Why You Need to Clean Your Fish Tanks Properly
Tank cleaning, or rather tank maintenance, is essential for good fish health and an attractive appearance. That being said, there is a right way and a wrong way to maintain an aquarium.
Many people try to do everything in just a few hours and then simply repeat that same process in a few weeks.
I have found it better to take an approach that relies less on marathon style cleanings and more on focused water chemistry management.
Be Ready for Every Cleaning Type: Tools and Supplies You Will Need
Before you begin cleaning a fish tank, it is very important to have some basic tools and supplies onhand.
This list is not dedicated to just one method of cleaning an aquarium. It is meant to be a comprehensive list of everything you will need for every type of cleaning.
Step Stool – Most aquarium stands are 2 to 3 feet high. Unless you are around 6 feet tall, reaching the bottom of the aquarium or the back is going to be difficult. Leaning against the aquarium can weaken the seams and cause leaks.
Having your armpit or inner elbow leaning on the rim of the tank is also a good way to damage the seals. Even if you are using a seamless aquarium, pushing on the walls of the tank can weaken it.
Battery Powered Gravel Vacuum – Check-ball style siphons are far too disruptive. Battery powered aquarium siphons will clean the tank without causing unnecessary waves in the water.
Small Wash Basin – For cleaning ornaments and filter parts
Algae Scrubber or Plastic Blade
Aquarium Safe Sponge
Notebook – Keep track of water chemistry changes over time. This will help you adjust the tank water during emergencies so that you do not create additional stress on the inhabitants.
Water Quality Needs
Bubble Up Filter, and Pump – Useful for clearing debris after using a siphon. They are also useful for preserving the biofilter, and adding custom media for water chemistry adjustments.
Activated Carbon and Zeolites – These are very important to add to the bubble up filter after a water change or gravel disruption. The zeolites will lock up ammonia and reduce it to nitrites.
Filter Floss – Essential for removing free floating debris from the tank.
Airstones – Adding extra air can help improve water circulation in the tank and help debris get to the filters faster.
Water Chemistry Needs
Water Conditioner – Important for removing chlorine, chloramine, and other toxins commonly found in many fresh water supplies.
Water Testing Kit – Make sure you have test strips for ammonia, pH, general hardness, carbonate, chloride, nitrates, and nitrites.
pH Adjustment Kit – Use instead of water changes when pH is outside of optimal for the inhabitants of the aquarium.
Water Softening or Hardening Agents – Aquarium water will increase in mineral content over time. You will usually need water softening pillows within 3 months of starting a new aquarium.
Nitrate and Nitrite Absorbing Pads – These should not be necessary unless your overfeed, overstock, or do not have enough plants in the tank. You may also need these absorbers after medicating the tank because antibiotics disrupt the biofilter.
Aquarium Salt – You may need this for live bearers and other species of fish.
Plant Care Needs
Plant Care Tool Kit – The kit should includes scissors, a spatula, and tweezers. These tools make it easier to trim plants, as well as propagate them.
Aquarium Plant Fertilizer – You may only need this during the first year of operation in a new tank. After that, the tank should have plenty of nutrients and minerals for the plants.
Trace Element Fertilizer – May be necessary for some plants that have specific nutritional needs that may not be met by the other inhabitants of the tank.
Miscellaneous Cleaning Supplies
Gallon Sized Plastic Bags – Float new water in plastic bags for about 30 minutes so that the temperature equalizes with water in the freshwater aquarium.
Extra Air Tubing
Suction Cups – Bubble up filters tend to float, as do airstones. Suction cups make it possible to control where these devices are in the tank.
Air Control Valves – Fish may roll, dart, or wobble in place when there is too much air in the tank. Air control valves can be used to lower the volume of air being pumped out by airstones.
Check Valves – A loss of pump action can generate a siphon effect that causes the water to back flow out of the aquarium. This will continue until the water is below the inlet of the filter.
Regular Maintenance: 6 Ways to Keep Your Fish Tank Clean, and When to Use Them
Each of these cleaning method will entail removing the hood. This is the perfect time to remove mineral deposits from the divider between the bulbs and the aquarium.
For safety sake, you will also need to shut off electricity to all devices operating in the tank. I like to keep all my plugs on one surge strip so that I don’t forget one or more by accident.
Some cleaning methods can span several sessions over a few days.
Always replace the aquarium hood after each session and turn the power back on.
Non-plant inhabitants of an aquarium get very stressed by changes to their home. They will be more inclined to jump out of the tank during these times.
After each session, you must scrub your hands and arms. It also a good idea to change your clothes and take a shower. Fish diseases, including TB, can be transmitted to humans.
Method #1: Live Plant Maintenance
Depending on their rate of growth, you may need to do this weekly or on a monthly basis.
- Fast growing plants – trim 50% each time you do plant maintenance
- Medium rate of growth – 25 – 35% as needed
- Slow growing plants – one or two leaves as you see a need.
Here are the basic steps:
Remove leaves that show signs of disease or algae buildup first. If the plant is still too big, choose the largest, oldest leaves next.
If younger, smaller leaves are covered in algae, try gently scraping it off with a sponge. Be sure to address causes of algae growth to prevent future problems.
Divide any plants that need to be propagated.
Fertilize as needed
Method #2: Water Chemistry Management
If you are using water changes to manage ammonia surges, excess nitrates/nitrites, or to control pH, you are probably doing several things wrong. This may include:
- Overstocking the tank
- Not growing enough live plants
- Overfeeding the fish
Partial or complete water changes cannot and will not solve these problems.
Here are my recommendations for water chemistry management:
In a tank less than a year old, check and adjust the water chemistry as needed on a weekly basis.
Once the water is well aged and balanced, continue checking every 2 – 4 weeks to make sure no problems are cropping up.
Check the water in the tank for ammonia and nitrites. If you detect ammonia or nitrites and the fish are in distress at any time, follow Method 6 (below) for emergency care.
Otherwise, add about ¼ cup of zeolites for every 10 gallons of water. Place the zeolite filled stockings (one for each 10 gallons of water) near the filter inlet and around the tank.
Add a nitrite absorbing pad to your regular filter, or place it in a bubble up filter.
Monitor the fish for signs of distress until ammonia and nitrates reach zero.
Leave the zeolites and nitrite absorbing pad in the tank until both ammonia and nitrites reach zero. Continue checking the water every 24 hours.
Unless the fish are showing signs of distress, wait for the zeolites and nitrite pads to do their job.
Check for nitrates if ammonia and nitrites are zero. Since plants depend on nitrates for food, you should have at least some in the tank. Don’t let it go outside the recommended parameters on your testing strip kit.
If you see elevated levels, add a nitrate absorbing pad to a bubble up filter in the tank. As soon as the levels come back into a normal range, you can remove the absorbing pad.
Add more fast growing plants to keep nitrates down.
Test for general hardness. Compare these values to the optimal levels for the inhabitants in your tank.
It is possible that you will find levels well out of range for the inhabitants of your tank.
If they have been living in this level of hardness for some time, it means they have adapted to the water. Do not adjust the hardness suddenly, but do bring it into the optimal range for the inhabitants of the tank.
Use ½ the amount of recommended water softener or hardening agent. Monitor the inhabitants carefully for signs of distress. Test the tank daily to see how the hardness levels are shifting.
Re-check pH values. These may have changed if you had to add treatments for other water chemistry imbalances.
Compare the pH to the optimal values for the inhabitants of your tank. Unless you have fish and plants that need alkaline water, it is best to keep the tank as acidic as the inhabitants will tolerate. This is one way to help mitigate the effects of any sudden ammonia surges.
It can take a few days of adding pH adjustment solutions before the tank is balanced. Check daily before adding more chemicals to the water.
Check tank levels for carbonate. If carbonate levels are low, the pH is likely to destabilize often.
Since carbonate additives will raise the pH in the tank, you may not be able to correct this problem. Instead, you may need to continue adjusting the pH on a weekly or bi-weekly basis.
Method #3: Algae Management and Removal
Excess lighting, excess food, and not enough live plants are a recipe for algae growth, even if the water chemistry is good.
Doing a partial water change does not address the underlying causes of the excess growth.
Even worse, the water change will stress the fish and other inhabitants of the tank.
Evaluate all fertilizers and additives to see if they contain phosphorus. Phosphorus contributes to algae growth. Try to use other products that do not contain phosphorus.
Follow Step 3 of Method #2: Water Chemistry Management to lower nitrates (which algae feed on) to the lower end of the scale.
Follow Step 2 of Method #2: Water Chemistry Management. Free floating algae blooms are deadly because massive die-off spread toxic ammonia through the water.
If the inhabitants of he tank show distress before the nitrates are within acceptable levels, follow Method 6 for emergency cleaning.
Reduce light going into the tank by 10% every 2 days. Once again, algae die-offs may produce more ammonia than the biofilter can handle. Follow Step 2 of Method #2 Water Chemistry Management until ammonia and nitrites return to zero.
Do not adjust the light lower than what is needed for the plants in your tank.
For algae attached to surfaces, scrape it off using an algae scraper or sponge. Algae can adhere strongly to tank walls.
Do not be tempted to push hard while scrubbing the algae. It is very easy to weaken tank seams or cause other damage from excessive pressure.
If you have plastic plants, heaters, or decorations with algae on them, remove them and scrub them in hot water.
Some people recommend soaking them in bleach solution, however I don’t feel comfortable with any kind of chlorine in the aquarium.
If you have live plants, follow Method #1: Live Plant Maintenance to remove algae from them.
Add more plants to the tank to absorb more nitrates.
If you continue to have massive algae problems for more than 4 months, consider setting up a new tank and moving at least half the fish or other ammonia producing inhabitants into it.
Method #4: Gravel Cleaning
One of the really nice things about a battery powered aquarium siphon is they come with a filter bag that fits the siphon outlet. This allows you to clean the gravel without having to replace the water.
On the other hand, if you also need to do a partial water change, you can simply attach a hose to the siphon’s outlet and let it drain into a bucket.
Here are the basic steps for both types of gravel cleaning:
Install Bubble Up Filter and Air Stones. Both methods of gravel cleaning will stir up a good bit of debris.
The filter should be stocked from the bottom up as follows: mix 75% activated carbon and 25% zeolites to fill the filter cup halfway. Fill the rest of the space with an aquarium safe filter floss.
If you are not planning to do a partial water change, attach the siphon’s filter bag to the outlet.
Vacuum the gravel by gently pushing the gravel cleaner end into the gravel. Raise and lower the siphon to make the gravel drop back down. You will see large amounts of debris coming up.
When the water coming up is clean, move the siphon to the next area of gravel. Continue vacuuming until you are done with all the gravel in the tank. As you move the siphon, make sure the water flows back into the tank.
If you are planning to do a partial water change, make sure the tank is topped off 3 – 4 days before you vacuum the tank. This will give the inhabitants time to adjust to water chemistry changes.
Attach a hose to the siphon and make sure that the free end goes into a bucket.
Vacuum the gravel until you have removed the percentage of water you plan on replacing.
While the water level is lower, scrape algae, clean tank decorations, or tidy up the tank as needed. Contrary to other aquarists, I always scrape algae after dropping the water levels. This way, more algae gets caught in the sponge and less goes in the water.
Replace the water one gallon at a time using gallon sized plastic bags. Float each bag for 30 – 45 minutes.
Do not remove the bubble-up filter and airstones until the water is clear and water chemistry is balanced. Follow the steps for Method #2: Water Chemistry Management to complete this task.
Method #5: Filter Maintenance
Contrary to the beliefs of some, when you discard filter media, you are also discarding beneficial bacteria. This is why you should avoid completely changing the filter media.
Depending on the filter type, here are some things you can do the preserve the biofilter as much as possible:
If you use bubble up filters, leave 25% of the floss in the filter. Do not wash this 25%, rinse it, or remove anything from it. Unless the rest of the floss is extremely grungy, just rinse it with room temperature tap water and put it back in the filter.
For overhead cannister filters, change the filters as recommended by the manufacturer. Add a bubble up filter and fill it with floss. You can also use this filter for softening pillows, nitrate absorber pads, and any other required filter media.
Even in a well balanced tank with plenty of plants, activated carbon will only last so long. Change the activated carbon at least once a month.
Wait one to two weeks after other cleaning types to make filter changes. This will reduce burden on the biofilter as bacteria regain in population.
Method #6: Emergency Situation Tank Maintenance and Cleaning Cycle
People that say fish are stressed by a “dirty tank” and that you should do a full clean often, don’t take into account the following:
- Fish dart and bump into things when they are frightened. The slime coat on a fish is like a cat’s skin. It is extremely delicate and can be damaged easily by brushing, bumping, and scratching.
- It is likely you are removing essential bacteria that break down waste in the tank. This increases the risk of ammonia and nitrite surges. Both can lead to fish death, immune system collapse, and illness.
Now, this isn’t to say that rotting food, sludge, and excess algae should be left alone.
But, it is almost always better to adjust the water chemistry with chemicals and use better management methods instead of water changes.
Water changes are only appropriate in a few situations that include:
- During and after antibiotic treatment
- If some dangerous chemical gets into the tank
- If the inhabitants of the tank show signs of ammonia or nitrite poisoning
- You need to top off the tank to replace water lost through evaporation
From ammonia surges to other problems that require a rapid, universal response, you can use this method:
Condition the water.
BBe sure to use a water conditioner that neutralizes chlorine, chloramine, and other toxins instantly.
Test the water chemistry.
Remove and change all media in the main filters. This will disrupt the biofilter – however, it is also the only way to ensure all toxins are removed.
Install Bubble Up Filter and Air Stones (see Method #4 Gravel Cleaning, Step 3 for how to fill the bubble-up filter and install it in the tank.) Include a nitrite absorbing pad.
Drain water as needed and vacuum the gravel.
Remove and wash plastic toys and plants.
If plants are small or don’t have well established root systems, take them out and rinse them off in clean, conditioned tap water.
For larger plants, remove as many leaves as you can without causing serious harm to the plant.
Scrape any existing algae.
Replace toys and plants.
Top off the aquarium and reinstall the hood.
Wait 4 – 5 hours.
Test water chemistry again and make adjustments so that pH, hardness, and carbonate match the levels from the last normal test.
Since many poisons disrupt pH, you will need to check your maintenance notes to determine the correct parameters.
Test for ammonia and nitrites after 12 hours, then every 24 hours. Do another partial water change if fish show signs of distress.
Remove the bubble up filter and airstones once water is balanced.
Change all media in the main filter once more to ensure all toxins are gone.
Continue monitoring the tank daily for two weeks.
How to Clean a Used Fish Tank
Cleaning a used fish tank is no different from cleaning one that you set up on your own.
If tank already has inhabitants, use the six methods listed in this article as needed.
How to Clean a Fish Tank With Eggs
It is best to avoid doing water changes while eggs and young fry are in the tank.
Use chemical and filter based adjustments to control water quality.
If you have to do a water change, try pushing as many eggs as possible into a pen so they are not sucked up by the siphon.
How to Clean a Small Fish Tank
You can use all six of the methods described in this article to clean a small fish tank.
These methods and tools are easily scaled to work in 1 gallon tanks as well as for use in tanks that hold hundreds to thousands of gallons.
As you can see, having a clean tank isn’t so much about marathon cleanings that occur on a set schedule.
It is very much about understanding how water chemistry works and the impact of each living thing in the tank.
Learning how and when to use these six methods for cleaning an aquarium will make it much easier to keep all inhabitants of the tank healthy and happy.