How to keep fish tank clean without changing water

How to keep fish tank clean without changing water

It is a bit easier to keep big aquarium bio balance in check to not change water much more. But you still will have to do it!

There are many ways of keeping fish tank clean without changing the water for a long time so please read the whole article!

Small aquariums need the same practical equipment as large ones. The heater and filter are especially important. A good lighting fixture is great if you want to keep plants or admire your fish.

How to keep fish tank clean without changing water

Stability in a fish tank

Compared to the natural environment, the mini aquarium is very small, but choosing the right fish and plants will not be a problem. The main thing is that the fish has enough space for its normal life.

Some fish, for example, the siamese fighting fish, even prefer small aquariums, this is due to the fact that many small fish live in nature in ditches, often even in large puddles.

The biggest problem in some fish tanks is the low volume of water. And as a result, any changes in it are instant. In a larger aquarium, the changes in water composition due to contamination are not as significant as if the same amount enters a mini aquarium.

For comparison, one gram per 100 liters of water will give a concentration of 1 milligram per liter, and the same gram per 10 liters will give 10 milligrams per liter. This means that any shift in the balance – overfeeding, fish death, rare water changes, instantly affects the state of the small aquarium than big.

The only way to avoid all this in a small aquarium is to regularly monitor the water parameters, maintain, and most importantly, moderate and adequate feeding.

In small aquariums, you will need to change the water anyway but it is possible to make the process longer.

Keeping fish tank clean

Caring for all aquariums is very simple and is based on the same principles. Replacing some of the water is key, little and often, that’s the golden rule. It is very common for aquarists to clean the tank monthly and replace all the water.

But only in one case do you need to change more than 50% of the water in the aquarium – if an emergency occurs. In nano aquariums, large water changes still introduce instability and imbalance. It is a good habit to change no more than 10-15% of your aquarium water at a time. If you need to replace more, break it up several times. Three times 10% is better than one 30%.

Filter care

In aquariums, there is the simplest internal filter – a pump with a sponge inside. Never wash this washcloth in running water! By doing this, you kill the beneficial bacteria that are involved in the nitrogen cycle. Just choose a finely porous one!

They look identical at first glance, they have different pore sizes, and fine dirt can fly through the large pores and return back to the aquarium. This will greatly reduce the chance of instability in your mini aquarium.

Plants in a fish tank to reduce need for changing water

Living plants are needed in aquariums, as they help remove hazardous substances from the water – nitrites, nitrates, and ammonia. Plants in an aquarium provide additional insurance and reduce stress on the fish. It is also very convenient for growing some small species of plants, because in a mini-aquarium it is easier to create good lighting, and in large aquariums, the light simply does not reach the lower level in the required quantities.

To choose the right plants for your aquarium – read the materials on the Internet and talk to experienced sellers, they will always help.


The most important point to keep fish tank clean without changing water. The food that you give is the main source of problems and in some cases even the only one, of various decay products. The less you feed, the less dirt and the more stable the aquarium. Of course, the fish must be well fed, and your task is to maintain a balance between well fed fish and overfed fish.

A good way is to feed as much food as the fish eat in a minute so that no food falls to the bottom. Commercial fish food, flaked, is a good choice for a small aquarium, it sinks slowly and produces less waste, but also produces small waste and does not need to be fed excessively.

It is better to feed the fish in the new aquarium to them. When the balance is established, or you start bottom fish, such as catfish, you can add other types of food for a complete diet.

What fish can be kept in a fish tank to have low water change needs

Choosing a fish for a fish tank is quite a difficult task. It’s not enough to just pick a small fish, although it’s the same factor. It is also important not to forget that the fish you choose will live in a limited place, which means that you cannot stop at aggressive or territorial species.

A common mistake is to buy male Xiphophorus, dwarf gourami, or cichlids, they can be real bullies. And species of active fish, for example, zebrafish, get along well but can interfere with other fish due to their energy.

I recommend you to look at our article about aquarium cleaners. Having that kind of fish is a great way to keep fish tank clean without changing water for a long time.

A good choice for a fish tank is small barbs, such as cherry and many types of characin – neons, rasbora. Corydoras of all types are well suited for cleaning an aquarium, or an algae eater – otocinclus. Shrimp – Amano shrimp and cherry shrimp.

Why changing water is important for keeping fish tank clean?

Why changing water is important for keeping fish tank clean?

If you really think that you can keep fish tank clean without changing water you make a mistake. Please read this part of the article and I hope you will reconsider it! Changing water is an important part of maintaining a healthy and balanced aquarium. Why do this and how often, we will try to tell you in detail in our article?

There are many opinions about water replacement: books, Internet portals, fish sellers and even your friends will name different numbers for the frequency and amount of water to be replaced.

It is impossible to name the only correct solution, it all depends on many different factors that need to be taken into account.

In order to find the ideal option for your aquarium, you need to understand why we are changing exactly this amount of water, and not more or less. A mistake can lead to disaster, both in the event that we substitute too much and in the event that too little.

Reducing nitrate levels in water

If you do not regularly change the water in the aquarium, the level of nitrates (they are formed as breakdown products in the process of life) will gradually rise. If you don’t check their number, you won’t even notice it.

The fish in your aquarium will gradually get used to the increased levels and will only become stressed if the nitrate levels in the water are very high for a long time.

But any new fish is almost certainly used to a lower level, and when you put them in your tank, they get stressed, get sick and may die. In neglected aquariums, the death of new fish causes an even greater shift in the balance, and already old fish (weakened by high nitrate content), become ill. The vicious circle leads to the death of fish and upsets the aquarist.

Sellers are aware of this problem, as they themselves are often blamed for the death of fish. From a fishkeeper point of view, he bought new fish, put them in the aquarium (which is doing great), and soon all the new fish died, along with a few old ones. Naturally, the sellers are blamed, although the reason must be sought in your aquarium.

With regular water changes, nitrate levels are reduced and kept low.

In this way, you significantly reduce the chance of disease in fish, both new and long-term fish in your aquarium.

Water change stabilizes pH

The second problem with old water is the loss of minerals in the aquarium. Minerals help stabilize the pH of the water, that is, keep its acidity/alkalinity at the same level.

Without going into details, it works like this: acids are constantly produced in the aquarium, which are decomposed by mineral substances and the pH level remains stable. If the level of minerals is low, the acidity of the water is constantly increasing.

If the acidity of the water increases to the limit, this can cause the death of all living things in the aquarium. Replacing the water regularly brings new minerals into the old water and the pH level remains stable.

If you change too much water

Now that it is clear that water changes are important, you need to understand that too much, as well as too little, is bad. Although in general a water change is necessary, it must be done carefully, since any sudden changes in the closed world of the aquarium harm it.

Too much water replaced at one time can be harmful. Why? When 50% or more of the water is changed to a new one, it significantly shifts the characteristics in the aquarium – hardness, pH, even temperature change significantly. As a result – a shock for fish, beneficial bacteria that live in the filter can die, delicate plants shed their leaves.

In addition, the quality of tap water leaves much to be desired, namely it is used in most cases. It has an increased level of minerals, nitrates and chemicals for water purification (the same chlorine). All this has an extremely negative effect on the inhabitants of the aquarium.

By replacing water only partially (no more than 30% at a time), and not half at once, you make only small changes to the established balance. Harmful substances come in limited quantities and are utilized by bacteria. A large replacement, on the contrary, maintains a dangerous level and significantly upsets the balance.

Regularity is better than quantity

How to change the water in a fish tank? An aquarium is a closed environment with stable characteristics, therefore, a large replacement of water with fresh water is undesirable and is carried out only in emergency cases.

Therefore, it is better to regularly replace the water a little than rarely and a lot. 10% twice a week is much better than 20% once a week.

Aquarium without cover

If you have an open aquarium, you will notice a lot of water evaporating. At the same time, only pure water evaporates, and everything that it contains remains in the aquarium.

The level of substances in the water is constantly increasing, which means that in an open aquarium, the process of accumulation of harmful substances is even faster. Therefore, in open aquariums, regular water changes are even more important.

Fresh water

Tap water, as a rule, needs to be settled to remove chlorine and chloramine from it. Better to stand for 2 days. The quality of water varies in different regions, but it is better to assume that the water in yours is of low quality. God protects those who are careful, so try to change the water to tap water regularly and in small quantities, or buy a good filter to purify it.

Also, in different regions the hardness of water can differ significantly, for example, in neighboring cities there can be both very hard and very soft water.

Measure the parameters, or talk to experienced aquarists. For example, if the water is very soft, mineral additives may need to be added.

And in case you use water after reverse osmosis cleaning, they are a must. Osmosis removes everything from water, even minerals.

What is the best option?

For an aquarium, the minimum threshold for changing water per month is about 20% so it is not possible to keep fish tank clean without changing water. It is better to split this minimum into two 10% substitutions. It is more optimal to replace it once a week, about 20% of water.

That is, with a regular water change of about 20% per week, you will change 80% in a month. It will not harm fish and plants, it will give them a stable biosphere and nutrients.

The most important thing in changing water is regularity, gradualness and lack of laziness.