How to keep a fish tank clean is a problem for many new fish hobbyists.  Aquarium fish is fun to have as with all pets.  However, there is work to be done to keep them.  A lot of new fish hobbyists end up with a dirty fish tank not long after they have just started.  Often time, there is cloudy water, or the fish tank stinks.  Sometimes there is an algae problem or snail infestation.  In many cases, it seems to be impossible to keep the fish tank clean.  No amount of cleaning or water changes seem to work for long.

A healthy, well-maintained home aquarium should have crystal clear water, earthly smell or no smell at all, very little to no algae, few or no pest snail.  

One thing is certain; You can easily keep a fish tank clean with minimum maintenance if you do everything right.  As for how to keep a fish tank clean, there are certain steps we need to achieve our goal. 

The following are 10 tips on how to keep a fish tank clean.

(They are not necessarily in any order)

1. The fish tank must not be too small

A lot of new fish hobbyists started with very small fish tanks or even bowls.  It is often one of the very first causes.  While it is not impossible, anything less than a 5-gallon tank is hard to maintain and not recommended. 

When it comes to fish tanks, size does matter.  The larger a fish tank is, the easier it is to maintain it.  It is easy to understand that the more water there is, the less concentrated the pollution will be in the case if there is any pollution.   A larger body of water will also have more stable water parameters which are essential to the well-being of the fish.  

The 5-gallon is the bare minimum we would recommend.  A 10-gallon is a better choice since it barely cost more.  If you are serious about keeping fish for the long term, it is a good idea to get the biggest fish tank you can afford both in the budget and the responsibility.  You will benefit from the larger size of the fish tank not only in easier maintenance, but it will also give you more options in the long run.

If you have already made up your mind on what fish and how many fish you will get, it is a good idea to do some research on the necessary requirement on the fish tank size before you get anything at all.  

2.  You must have a sufficient aquarium filter

Every fish tank must have an aquarium filter running 24/7.   It is a mandatory equipment.  There is no way around it.  A filter is as important as the fish tank itself.  Without an aquarium filter, fish will die.  The filter is what keeps the aquarium nitrogen cycle going in a closed system like a fish tank.  It keeps all the toxic (produced from fish poop as well as leftover fish food) at harmless level. 

Make sure you know how to choose an aquarium filter is essential.  All the filters have a manufacturer recommended tank size on it.  Always choose at least one step above your fish tank size is a good idea.  There is, however, a limit.  As higher rated filter will have stronger current.  If the filter is rated too high for your fish tank, the water current will be too strong which might not be good for some fish species. 

3.  You need to do a fishless cycling to your fish tank before getting any fish.  

A well-maintained home aquarium must have aquarium nitrogen cycle going on in there 24/7.

In a lot of cases when there is cloudy water in a fish tank, it means there is a bacteria bloom.  The bacteria feed on organic waste to complete a nitrogen cycle is multiplying rapidly to meet the demand.   We must cycle the fish tank or rather the filter system, before adding the fish.  It is called a fishless cycle.   Once a fish tank is cycled, there won’t be cloudy water caused by incomplete nitrogen cycle. 

4.  Do not overstock your aquarium with too many fish

More fish means more mouths to feed.  More fish means more waste produced.  When there are too many fish in a fish tank, it will be harder to keep the water clean as so many fish are eating and pooping on a daily basis.  To make your job easier on keeping the aquarium clean, make sure you do not go overboard on the number of fish in the fish tank.  In this case, the fewer fish, the better.  Less waste produced will help to keep the fish tank cleaner.  

5.  Use a premium fish food

Not all fish foods are created equal.   A premium fish food is an investment.  They are more nutritious than regular fish food and easier to digest.  Because they have less filler in it.  Less filler in the fish food will produce less pollution in the tank water.  Some cheap fish foods will even break into fine dust when the fish try to eat them.  It makes a mess of the water quality.  

Some examples of the high-quality fish foods are Omega One Flakes and New Life Spectrum Pellets.  

6. Stop overfeeding the fish

Fish is completely different from us.  Since they do not need to maintain a constant body temperature, they do not need nearly as much food to sustain themselves.  When you dump too much fish food into the fish tank, there will be pollution. 

The extra fish food you feed to the fish will likely cause leftover in the fish tank.  Uneaten fish food will rot and create all kinds of water pollution including but not limited to ammonia, nitrite, phosphate.   In the case, if the fish have eaten all of the fish food you fed to them, more food still mean more organic waste is produced through the fish’s digestive system.  Even if the biological aspect of the filter is efficient enough to cover all of the ammonia and nitrite to the harmless nitrate though aquarium nitrogen cycle, the nitrate, and phosphate are not going anywhere.   These organic waste will cause an algae bloom.  

While an efficient aquarium filter system will keep the toxic pollution at bay, there is a limit to the maximum capacity.  If more ammonia than the filter system can handle is produced, there will be ammonia in the water.  While the physical filtration of the filter system might remove fish waste out of the sight, the pollution is still in the aquarium system since the water circulates through the filter. 

Leftover fish food will also be a food source for pest snails.  If you keep dumping fish food in the fish tank, you might see a pest snail infestation in no time.  

By limit the amount of fish food, you will keep the all the organic waste to a minimum.  At the very least it will help to make it harder for algae bloom to happen.   Less rotting organic matters in the fish tank will help to keep the water clean. 

The correct way to feed the fish is to feed them no more than once a day.  With no more fish food than they can finish within a minute. 

 7. Remove uneaten fish food immediately after feeding.  

Most fish species will only eat their food at the top and middle water level.  Once the fish food hits the bottom, they will ignore it.  Uneaten fish food creates more pollution than fish poop.  In this case, we recommend not only to reduce the feeding, but you can also slow down on the feeding.  For example, instead of throw in 30 pellets at the same time, you may throw 10 pellets at a time in 3 separate batches with some time in between.  So you will give the fish more time to finish the food before they hit the bottom.  

In the case there is still uneaten food after the feeding, we recommend to remove them immediately to avoid spoiling the water quality.  You can use a fish net to remove the floating fish food.   And a gravel vacuum is good for removing the uneaten food at the bottom.  

8.  Use a cleaning crew

Some bottom feeders including fish, shrimp, snails, are great cleaning crew if you are looking for a natural way to deal with uneaten food.  As the name suggests, bottom feeders will only eat their food at the bottom of the fish tank.  You do not need to worry about uneaten food at the bottom of the fish tank as long as you have bottom feeders in the tank.   My favorite gravel cleaning crew is Corydoras Catfish.  They are a schooling fish.  Make sure your fish tank has extra room for at least 5~6 of them.  

Some species of fish, shrimp, and snails are also great for algae control.  While you should not completely rely on them to get rid of the algae, they will definitely be a big help.  Some of the good algae eating species are Otocinclus Catfish, Amano Shrimp, Red Cherry shrimps, Zebra Nerite Snails.   

Whatever you plan to get, keep in mind that they will only help you to a certain degree.  Do not think they will make all the problems go away even if you are not taking good care of the aquarium.   

9. Limit the light exposure to the aquarium

The long period of light exposure will cause algae infestation in the aquarium.  The same thing will happen if the light is too strong.  When there are algae in the fish tank, the side of the fish tank will turn greenish, same goes for all the objects in the fish tank including the substrate.  In severe cases, the tank water can turn green as well.  Eventually, you won’t be able to see the fish.   To keep aquarium algae free or almost algae free is important to have a clean aquarium. 

To keep algae problem at a minimum, make sure the fish tank is not by the window.  So no sunlight and direct daylight will reach it.  If you use aquarium lights, please use an automatic timer to set the lights to turn on no more than 10 hours a day.   

10. Weekly Aquarium Maintenance

Even a well-established, healthy aquarium system can’t sustain itself forever without maintenance.  The nitrate and phosphate are not going anywhere unless you have covered every square inch of the fish tank with live plants while having a minimum amount of fish.  Otherwise, you will need to do a partial water change of 30~50% once a week to keep the organic waste in check.  Use an aquarium vacuum to remove as much debris as you can while removing the water from the fish tank.  You may also need to use an algae scraper to clean the sides of the fish tank. 

A home aquarium is easy to keep clean as long as you do everything right.

Let’s go over it one more time on how to keep a fish tank clean. 

1. You will need a fish tank of ideal size. The bigger, the better. 
2. It must have an efficient filter system. 
3. You need to cycle your fish tank before getting any fish. 
4. Once you are ready to add fish, do not overstock your fish tank.  The less the fish, the easier it is to keep the fish tank clean. 
5. Choose a high-quality fish food to keep the pollution at a minimum. 
6. Do not overfeed your fish. 
7. Immediately remove all uneaten fish food right after the feeding. 
8. Use a cleaning crew to help with getting rid of uneaten fish food, and algae control.  9. Limit the light exposure to the aquarium is the key to keeping algae under control. 
10.A healthy fish aquarium should be easy to keep clean with just weekly maintenance.