How to change the water in the aquarium with fish


How and how much to change the water in the aquarium, the frequency of water changes

How to change the water in the aquarium?

In this article we will discuss a fairly simple, but at the same time, a difficult question regarding the change of water in the aquarium. It is simple because there is no need to replace water in the aquarium. However, there are a lot of nuances and certain specifics that you need to know on this issue. The matter is further complicated by the lack of complete, comprehensive information on the Internet. As a rule, information about the change of water in an aquarium is either compressed, or one-sided, or only a certain part is covered.

No exception was our site. Here, for example, article Boiled, melted or distilled water for aquarium. It seems the article is good, but narrow and concise.

So let's fix this defect. As much as possible and fully consider the question: "How to change the water in the aquarium?" That in turn, will give us the opportunity to make the change of water as simple and effective as possible.

For convenience, let's break down the article into the following sections:








Many novice aquarists are faced with different opinions about the need to change the aquarium water. Often in the forums or from friends you can hear the phrase: "That I do not change the water at all and .... everything is OK" or "I rarely, rarely ... and also OK." Here that, at the beginner and there is a stupor! How so? I’ve furnished the whole balcony with buckets, how I carry a water carrier from the bathroom to the aquarium, but it turns out that this is “monkey work” !? Without tormenting for a long time, I will answer you - do not listen to these "uncles and aunts"! They mislead you. AQUARIUM WATER MUST BE CHANGED!

And the thing is this! In the process of vital activity of all aquatic aquatic organisms (inhabitants), the aquarium itself, or rather, the water becomes clogged. For example, an excess of food, fish feces, dead leaves of plants and other organic matter. All this "dirt" turns into the most terrible poison - ammonia, which is destructive for all living things in an aquarium. Further, the nitrifying bacteria that are in the water, the filter and the soil "decompose" ammonia to nitrite (poison), then nitrate ("weak" poison), and then the remains are converted to gaseous state and leave the water.

So, no matter how many useful nitrifying bacteria are in the aquarium of colonies, no matter how many live plants are in the aquarium, which also partially absorb ammonia, no matter how powerful the filters are ... no matter, the above poisons tend to accumulate. And you can bring them ONLY REGULAR REPLACEMENT OF WATER TO CLEAN.

What happens in an aquarium for those who do not change the water for a long time? Many aquarium fish tend to adapt and live in the worst conditions - get used to the poisons. However, this function of "survival in any conditions" is not eternal. In fish, irreversible changes occur in the internal organs, mucous membranes and gills. Fish weaken, their immunity falls. And the “Doomsday” comes when an outbreak of a bacterial, fungal or infusorian attack occurs ... not many survive!

In total, the change of aquarium water is one of the most important ways to maintain "health in the aquarium", one cannot do without it. Laziness in this matter is a fatal mistake!



There is such a non-contagious sore in fish, called Gas embolism. In a nutshell - this is the entry of small air bubbles into the blood vessels and blood of fish. As a result, there is a blockage of blood vessels. Fishes begin to swim sideways, the behavior becomes alarming, fearful. The fins and the whole body begin to tremble convulsively. The movement of the gill covers slows down, and then completely stops ... further death!

A frequent cause of gas emboli is inadequate settled water for an aquarium. The fact is that tap water (tap water) is excessively saturated with air bubbles that are so small that they are not even visible to the human eye. Just imagine how much water “poured through the pipes” until it reached your tap!

Thus, filling the tap water in an aquarium with fish - YOU ARE VERY RISK. Yes, in practice, everything can do, but this is a game of Russian roulette.

What happens to water if it is defended? What happens is that small bubbles gradually merge and come out of the water. Water saturation by air decreases, the risks are reduced to zero.

In addition, it is worth noting that in the process of settling water for the aquarium, heavy and harmful compounds, for example, chlorine as sediment at the bottom of the container and film on the surface of the water, settle.


Everything is simple and should not cause much difficulty. The water in the aquarium should settle in a container with a wide neck: a bucket, a basin, an enamel saucepan. You understand that in a bottle with a narrow neck, excess air goes out poorly. Container for sludge should not be metallic, rusty or made of toxic substances or paints. Plastic buckets, perhaps the best and easiest option for defending aquarium water.

About time! ... The longer the water settles, the better! I personally defend the water for 7 days - this is convenient and coincides with my Sunday schedule for changing the water in the aquarium. In general, such terms of water settling 1-14 days roam the Internet.


But this is really a problematic issue for owners of large aquariums and not large apartments! How to defend 50, and then 100 liters of water?

If this is a new aquarium and the first launch of the aquarium is made, you can immediately fill in the aquarium with tap water, defend it and at the same time add air conditioners to improve the quality of water.

If water is needed for replacement, then our first glance is the only rational option is to purchase construction containers (plastic buckets for mixing mixtures) for 50, 100 liters.

Other ways to prepare aquarium water in the first place include: boiling, freezing water, as well as its purchase of water in the store. See more about this. HERE.

Also, aquarium water can be prepared using special air conditioners such as: Tetra AquaSafe, AMMO-LOC, Sera aqutan and others.

Here is a video about one of them:


Almost in all books, on all sites, they write standardly what needs to be changed weekly? part of the water from the total volume of the aquarium. This is a generally accepted norm, BUT NOT DOGMA. Here, look, please statistics of the survey, which is conducted on our site.

How often do you change the aquarium water to fresh?

As you can see, everyone changes the water in different ways and the weekly replacement of aquarium water is not a dogma! Why? It's very simple - everyone has different aquariums, different fish, plants, and so on. For example, there are fish that love the "old" water and the frequent change of water only annoys them (the family of labyrinth fish). The abundance of living plants, also reduces pollution in the aquarium. In the end, someone has a large aquarium, someone has a small, someone has a big fish, and someone has a small one.

All this individual specificity of the content of fish excludes the concept dogma number and frequency of substitution of aquarium water. And there is only one advice - you should adapt yourself and you should come to the conclusion about how often and how much water you need to change in your aquarium. In this case, you must take into account the volume of the reservoir, the population of the aquarium, the individual characteristics of the fish, the presence or number of plants, the filter power, the presence of ion exchange resins in the filter, and so on.


Finally, I want to give attention to the beginner aquarists, that it is only necessary to change the aquarium water after cleaning the aquarium, and not before.

That is, first we:
- clean the filter and other equipment;
- wipe the walls of the aquarium;
- we thin and cut the plants;
- siphon soil;
- produce other manipulations and permutations;
- and only then we replace part of the water with fresh one;

If you have any questions, any comments on the article, please leave them in the comments - we will discuss.

Useful video about changing aquarium water

How to change the water in the aquarium with fish?

The fish living in the aquarium require constant maintenance of a certain composition of water, and, despite the filtration and aeration carried out, there comes a time when you have to change the water in the aquarium. This is a mandatory process, which can be carried out in part or in full.

Novice aquarists wonder: how to change the water in the aquarium with fish, should it be defended? It is advisable to check the tap water for the content of harmful substances in it, and if they are present, the water should be defended for three days, and the use of special cleansing compositions is also permissible. If you do not do this, you can simultaneously change no more than 20% of the composition of the water in the aquarium.

Replacing the full amount of established water in the aquarium, and forming a particular ecosystem, should be extremely rare, it negatively affects the fish and plants, they are difficult to get used to the new water and often die. Even making a partial replacement of water, it is worthwhile to worry about maintaining its temperature, as well as gas and salt composition.

If there is a need to completely change the water in the aquarium, you should temporarily relocate all living organisms to another tank, completely clean the aquarium, fill it with settled water, and after a few days when the biological balance is restored, return the fish and plants to their original place.

Features of the water change for the aquarium with cockerel fish

Cockerel fishes best of all feel in big aquariums, water in which not less than 27 degrees. How to change the water in the aquarium with cockerel fish? There are no special requirements, you just need to know that this fish does not need frequent changes of water. In this case, the cock carries both soft and hard water. Changing the cockpit water to a new one, it is necessary to add the old part, while necessarily observing the temperature regime. At the time of water replacement, the fish should be deposited in another container.

❶ How to change the water in the aquarium :: how to change the water in a small aquarium :: Care and upbringing

Tip 1: How to change the water in the aquarium

If you decide to start an aquarium with fish, then you just have to know how to care for animals, clean the aquarium and change water. After all, its condition for fish is as important as the quality of inhaled air for humans. The main mistake of novice aquarium lovers is that they do not know how to properly change water and in what quantity.

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You will need

  • - siphon with nozzle;
  • - additives to neutralize harmful substances;
  • - gauze or mesh.


1. Your main task in caring for an aquarium is to maintain a stable temperature regime and chemical composition of water, that is, biological balance. The wording "change of water" can lead newbies into a kind of delusion, you might think that water should be completely drained from the aquarium and fill fresh. Do not do anything like that.

2. Before proceeding to replace part of the water in aquariumthink about cleaning the walls and soil. Using a special nozzle in the form of a siphon, drain ten to twenty percent of the water from the aquarium. In the absence of a siphon, water is drained through a plastic tube of small diameter (one and a half centimeters). Put gauze or net on the end of the tube so that the fish do not accidentally suck in there.

3. Use cold water from the tap, which is recommended to pre-settle in an open glass or enamel pot for two to three days. Never use warm water, as it contains a large amount of harmful impurities that are undesirable to the health of fish. To facilitate the process of replacing water in aquarium, you can purchase special additives in the pet store to neutralize harmful substances. Such additives will allow you to change water at aquarium without prior sedimentation.

4. If you change regularly water, conscientiously take care of your aquarium and use a special coal, the likelihood of emergency situations (in which a complete replacement of water is required) is almost zero. But if suddenly the water begins to bloom and mucus appears (the so-called fungus), you cannot avoid a complete replacement of water. This measure is radical, but in turn helps to save water inhabitants from death.

Tip 2: Why dream of fish in an aquarium

Fishes in an aquarium may foreshadow marriage, pregnancy, travel, change, and more. Of great importance is the purity and transparency of the water, as well as the number, size and color of fish.

If a person has a dream and, on waking up, wants to know what fish dream about in the aquarium, then it is worth noting that such a dream always foreshadows changes that should occur in the very near future. I must say that dreams of this kind are most often seen by women, because water is the female element.


If the fish in the aquarium dream of a young girl, this means that she will soon get married. However, the prediction can only come true if the aquarium has a large volume, and the number of beautiful fish floating in it cannot be counted. If the color of most fish is bright and variegated, then the future husband will be a wealthy and even rich man. If in a dream among the thickets of an aquarium floated fish of different colors, then this is not a good sign: there will be no understanding in marriage, everyone will try to take the place of the head of the family. This can occur due to the large difference in age between spouses, differences in religion and the usual outlook on life and the upbringing of children.
The purity of the water in the aquarium is very important. If it is transparent, like a tear, then the coming changes will bring only joy and pleasure, but if it is muddy and dirty, then do not expect a good one. If the sleeper sees how someone changes the fish's water, then in life you should expect dramatic, dramatic changes for the most part positive. If you dream of fish in an aquarium that the sleeper feeds himself, then the coming days will be monotonous and monotonous, filled with the usual routine work. If the sleeping man feeds the fish with pleasure, then the long work on some project will come to an end and will bring its worthy results.

What else predicts such a dream

If you are dreaming of dead fish in an aquarium, then sad events and news cannot be avoided. If, for some reason, the aquarium is empty, the sleeper may be trapped in failure and deception. If there are only two fish in an aquarium, then often the interpretation of a dream is connected with a new novel that is just emerging. It is very important to remember how the fish behaved towards each other: if they floated all the time together, then the novel could turn into something more, if the inhabitants of the aquarium dispersed in different directions, so will its outcome.
A goldfish swimming in an aquarium promises a sleeping profit. If she is having fun and playing in clear water, it’s worth preparing for an interesting and exciting journey associated with some expenses. If the inhabitant of the aquarium swims alone, then the sleeper can be sure: the event he had been waiting for will happen soon. And the larger the size of the fish, the more fully fulfilled what he had dreamed of. If a young woman catches fish in her sleep with her hands, then this may promise an early pregnancy.


Remember that in an aquarium not only fish live, it has a peculiar biological environment, the components of which are tightly interconnected. Therefore, if one link of the system begins to hurt and collapse, this situation will affect the remaining links.

Replacing aquarium water

Water for aquarium fish must be supported by a certain composition, in which the proportion of substances from the decay of organic matter is regulated. Despite the fact that in many respects equilibrium is achieved through the use of filtration, it is necessary to carry out regular replacement of water. Deciding how to change the water in the aquarium, its owner must represent what kind of results he wants to achieve.

How to change the water in the aquarium

Replacing the water in the aquarium is an obligatory process for its maintenance. There are partial substitution and complete replacement of water.

Partial water change

Partial substitution in a freshwater aquarium is necessary to maintain the balance of the formed environment due to the fact that it evaporates and changes its composition. However, before changing the water in the aquarium, time should pass from the day of its launch: at least 2 months.

The frequency of partial replacement procedures is once every 1-2 weeks. Replace recommended 1/5 of the total.

Beginner aquarists face the question: how much to defend the water for the aquarium? If tap water does not contain chlorine and phosphates, then it can and not be defended. To check the presence of harmful substances should be tests. Если указанные соединения есть в водопроводной воде, то отстаивать ее можно дня 3.Also, the preparation of water for the aquarium can be carried out using special compositions to change the chemical composition of water. With a sufficiently large volume of the aquarium (more than 150 liters) without special preparation, you can replace up to 20% of water in it.

Deciding what kind of water is needed for an aquarium when carrying out a partial substitution, should be guided by the capriciousness of the species of fish and plants that inhabit it.

Big substitution of water in several stages

The big substitution is the replacement of a significant amount of water in several stages during the week. Such a replacement of water in aquariums is used when you need to repeatedly reduce the level of substances accumulated in the water. After such a procedure, the fish become more active. But it should not be made too often.

How to change the water in the aquarium gradually, but in large volumes?

Consider the example of an aquarium in 100 liters. If there is little vegetation in it, such a change of water in the aquarium can be done as follows: drain 80 liters and add 40 liters of new water, and then after the remaining 40 liters.

For aquariums densely populated with fish or planted with algae, this option super-substitution is not acceptable: you can replace up to 60% of the total at one time.

It is convenient to use super substitution, which takes place in several stages. 60% of the volume of water in the aquarium is drained and only 30% is added, then half of the remaining is discharged and the same volume is added. The last manipulation is repeated 2 times, then add another 30% to the full volume of the aquarium. All stages of this super substitution take place in one week. At the same time, the concentration of harmful substances in water decreases to 8% of its initial volume.

Full replacement of water in the aquarium

Complete replacement of all water in established aquarium systems is extremely rare and in exceptional cases. It adversely affects its inhabitants: the leaves of plants grow brighter and die off more quickly, and some fish may die.

What water is needed for aquariums when it is completely replaced? Water should be prepared in advance, otherwise all the benefits of such a replacement will be leveled by a sharp change in pH-environment and water temperature, which, in turn, will be stress for fish. Therefore, for effective replacement of water it is often necessary to change its chemical composition.

How to change the water in aquariums with sea water

The main question for novice marine aquarists is how to change the water in an aquarium with sea water, without disturbing its composition. The main reason for its replacement: an increase in the concentration of nitrites and nitrates in water.

Replacing water in an aquarium with a marine bio-system is different from a freshwater aquarium. Firstly, if there are whimsical hydrobionts in the aquarium, it is recommended to take water either distilled or passed through reverse osmosis. There are aquarists who successfully use tap water to replace small amounts of water in fish aquariums. However, beginners should be aware that such a replacement is far from being possible for all types of marine fish and the water must be pre-filtered.

There are many discussions among non-professional owners of saltwater aquariums on how to change the water in aquariums with sea water. It is believed that the monthly substitution, which occurs in 5-20% of the water in the aquarium, does not give the desired effect if the aquarium is heavily polluted. But replacing large amounts of water destabilizes the balance. Therefore, the frequency of this process and the volume of water being replaced are determined by the efficiency of a particular aquarium. The need for an emergency replacement will be recognized by conducting regular water testing using tests.

The process of preparing water for the aquarium is simple. The purified water dissolves salts, which include: MgSO4x7H20, NaCI, KBr, MgCl2x6H2O, SrCl2x7H20, Na2CO3, CaCI2, KCI, H3BO3, NaHCO3, NaF. It lasts 3 days and it is better to add salts in a certain sequence.

Full replacement of water in the marine aquarium is carried out only as part of its restart.

How often to change the water in the aquarium?

The question of the frequency of changing (or changing) aquarium water very often causes controversy both between amateurs of the aquarium business and in the community of professionals. For everyone, however, it is completely obvious that the chemical composition and balance of the aquatic environment is very important for fish and other animals. Consequently, substitution should not dramatically change the conditions of their usual existence.

Why completely change the water?

Full replacement is done in exceptional cases, and for this there must be good reasons, namely:

  • progressive water bloom caused by the rapid growth of green algae;
  • the appearance of fungal mucus on the walls of the aquarium and decorative elements;
  • severe contamination and acidification of the soil substrate;
  • infectious disease of fish or plants, caused by the introduction of infections into the aquatic system.
Full replacement of the aquatic environment is almost always a negative impact on the aquarium living creatures.

The fact is that in fresh water it falls into the atmosphere of an unformed ecosystem. In addition, even despite the preparation of new water, its parameters will still be different from the usual.

It should be understood that such a replacement always leads to a strong stress of ornamental fish until they die. Vegetation also responds to new conditions: leaves of plants can turn white after moving to fresh water.

Thus, a complete replacement is a restart of the aquarium, when the creation of an ecosystem begins anew.

Partial water changes: the meaning and content

Replace the water in the aquarium is necessary. Partially. And here specialists have almost no disagreements. Although there are owners of domestic water bodies, who argue that the aquarium can work for years with the same water. It is believed that an ideal balance can be achieved when fish, plants, technical devices for filtering and maintaining water quality work in concert, creating a balanced ecosystem that is as close as possible to natural conditions.

Indeed, there is information that some owners of ornamental fish do not produce substitutions for years. But if you carefully read the data, it turns out that we are talking about sparsely populated aquariums, where the waste of guests is quite insignificant.

In all other cases, it is necessary to replace the water, since a completely closed environment does not live long. In nature, it is impossible to meet a reservoir where there would be no flow and at least a partial renewal of water. Otherwise, the reservoir degrades and dies.

What is the meaning of the substitution? In simple terms, it mimics the natural environment where there is water circulation. Even the most insignificant. The fact is that in an artificial reservoir harmful substances are inevitably formed - toxins and nitrates, which appear in the process of life activity of living beings and plants. The decrease in the concentration of such substances in the aquarium is what the main meaning of the partial substitution is.

It is necessary to note that if, for example, 1/5 or even ¼ of the old water is replaced with fresh water, the balance of the established ecological environment will be partially disturbed. But these violations are not critical. It will take one or two days, and the balance will recover by itself.

Replacing half the volume of the aquarium ecosystem will process much longer. It will take 2 weeks until the lost balance is restored, and during this time some fish that are sensitive to changes in water parameters may even die.

How often should the aquarium water be changed?

Many experts argue that this frequency depends on the age of the aquarium. It is no secret that in his life he goes through all stages of existence: the aquatic system is new, young, mature and old.

Substitution in just running pond. When the new aquarium is launched, experts recommend not to interfere with the state of the aquatic environment for 2-3 months. At this time, the formation of the internal ecological mini-system takes place, and intervention is permissible only in extreme cases.

Substitution in a new aquarium. After this period, when the young aquatic system was basically formed, you can start replacing part of the water once a month. The recommended dose is not more than 20% of the total. It is necessary to consider the size of the aquarium. So, if in a 200-liter container it is possible to fill in tap water, then for a 30-liter jar 6 liters of water must be defended for two days. Such procedures should be combined with cleaning the soil (if necessary) and the walls of the aquarium.

Substitution in a mature aquatic system. About six months later, the aquarium habitat enters a mature phase. Replacements should be made in the same dose and with the same frequency, with simultaneous cleaning of the aquarium. If the ecosystem is stable, then you should not disturb it once more with your intervention.

Replacing water in an old aquarium. Some experts say that after 1.5-2 years the aquarium is aging. For its rejuvenation, it is recommended to temporarily switch to another water replacement schedule - 2 times a month. Cleaning the soil after draining part of the water becomes mandatory, and if there is such a need, the soil can be gently removed and rinsed thoroughly. Frequent water changes are advised to do for two months, after which the rejuvenation of the entire system should occur, and the aquarium will function stably for another year or two.

Replacing water in a marine aquarium

This procedure is slightly different from the freshwater version. The most important thing is that the water should be prepared, and ordinary tap water is not suitable for substitution (although some aquarists use it in small doses).

It is better to use distilled water, which is added to the finished salt according to the instructions. Such salts are sold in pet stores, their choice is quite wide. Suffice it to mention the salt compositions of RED SEA CORAL (Israel) or Tetra Marine (Germany).

The frequency and volume of sea water being replaced are subject to heated debate by professionals. Various options are discussed, but most owners of saltwater aquariums talk about a 25 percent dose of the replaced aqua. What all professionals and amateurs are unanimous about is the need to replace it based on the specific conditions and parameters of the marine artificial reservoir.

Water changes always help to prolong the life of the aquarium ecosystem. And here the most important factor is not only the volume of replaced water, but also the regularity of this operation.

Video on how to change the water in the aquarium:

Is it necessary to change the water if one of the fish died :: how to change the water in the aquarium :: Aquarium fish

Tip 1: Do I need to change the water if one of the fish died

Often, inexperienced aquarium owners rush to replace all the water in a tank if one fish dies, as they fear the contamination of the aquarium. So is it really necessary to completely change the aquarium water, or are there other rules for dealing with an aquarium in which one of its inhabitants died?

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Change or not change

If only one fish dies in the aquarium and the water looks clean, it is not necessary to change it, because after changing the water, it will be necessary to wait for the restoration of the ecosystem and biological balance. Therefore, it is enough just to add fresh water, renewing the old one. If the fish has died from an infectious disease or has lain in the aquarium for several days, the water should be replaced, while washing out the aquarium.
When adding fresh water to the aquarium, at least one third of the old water should remain - at the same time, fresh water should have similar hardness and temperature indicators.
If you still need to clean the aquarium, you need to remove all live fish and plants from it, wash, disinfect and dry. After that, new water is poured into the tank. In the first few days a short-term bacterial outbreak with water clouding can be observed in the aquarium - no need to worry, it will pass by itself. After that, as the water becomes transparent again, plants can be returned to the aquarium, and it is advisable to launch the fish in about a week. Replacing water is often the most effective way to get rid of bacteria, but for fish it is a lot of stress, so you should not abuse it.

How to change the water

An electric or vacuum pump is great for changing the water in an aquarium. A siphon will also do well with this task, with the help of which the walls and bottom of the aquarium are easily cleaned of food and residue residue. To prevent the water from turning green, the aquarium should be placed away from sunlight and turned off artificial light at night. In addition, it is necessary to periodically remove excess plants from it and feed the fish less so that the water is not contaminated by the remnants of food.
Somiki-antsitrus, which slide along the aquarium walls and eat plaque on them, will also help to clear the water.
Partial change of water in the aquarium should be done every week, changing it to 1/5 of fresh water. In order for the water to always be clear and transparent, you should launch mollusks and daphnids into the aquarium. Many owners of aquariums are trying to clean glass containers with snails, but they are not very effective in doing this and besides they are spoiling quite a lot. Water problems are usually characteristic of "young" aquariums - later their own ecosystem arises in them, the situation normalizes independently. The main thing - to follow the rules for the care of the aquarium.

Tip 2: How to change the water in a small aquarium

Mini-aquariums - an attractive interior decoration. But unlike large tanks, equipped with all necessary equipment, there are some problems with care. If you follow the basic rules, including the replacement of water, you can avoid the flowering of the aquarium and create fairly tolerable conditions for the fish.

You will need

  • - soft distilled water;
  • - net capacity;
  • - bucket;
  • - scraper.


1. It is believed that a small aquarium is easier to clean than a large one. However, this is the first misconception of inexperienced aquarists. It requires more frequent replacement of water, because the products of decomposition of fish waste are accumulated here most of all. In addition, intensive plant growth can cause a lot of trouble.

2. The water in a small aquarium should not be completely changed. It is enough to replace up to 1/5 of the total volume. This should be done quite often - once every 3-4 days.

3. Replacement water should only be soft, room temperature, so you should have a constant supply. Only tap water from clean dishes that should be used only for this purpose. To defend the liquid must be at least three days.

4. Replacing water in a small aquarium is not difficult. Calculate the required quantity for replacement. For example, in an aquarium with a capacity of 10 liters, it is necessary to change 2 liters (1/5 of the total volume).

5. Scoop out the required amount of water with a special scoop with a long handle. Scrub the walls of the aquarium and add fresh soft water. Then collect water in a clean dish and leave it to stand until the next procedure.

6. The water in the mini-tanks evaporates very quickly. Check its level regularly and top up if necessary.

7. Fully change the water in the aquarium should be as rare as possible, because it violates the biological equilibrium. However, this must be done once a year to transplant plants and clean the walls of the aquarium and filter.

8. To replace the water completely, remove the fish and place them in a jar for a while. Drain fluid with a hose. Remove excess algae. Clean the rocks and walls of the aquarium.

9. Then pour the settled water. Add bacteria and let the aquarium stand for a couple of days, then run the fish into it.


For dwelling in a small space, choose guppies, gourami and tetra. These fish feel pretty good in mini-aquariums. Also in the pond you can settle a cockerel, neons look beautiful. If the fish have grown to a rather large size, they need to be deposited in a larger tank.

Very impressive look and feel good in a small aquarium, not only fish, but also other marine and freshwater inhabitants, such as shrimp.

Why does the water quickly grow turbid?

Muddy water in an aquarium with fish is perhaps the most common problem that concerns both beginners and experienced aquarists. Through trial and error, we have to figure out why muddy water appeared so quickly. The causes of this phenomenon can be different, ranging from a bacterial outbreak, improper feeding and irregular water renewal. A number of factors may also be the source of this problem. When the elimination or elimination of the causative agent of water turbidity in an aquarium occurs quickly, then the biological balance in the water is fully restored.

Sometimes this trouble provokes the death of fish, plants and invisible microorganisms. The first thing to do is to find out why the water becomes cloudy quickly. The second is to gradually eliminate the shortcomings.

Causes of Aquarium Water Turbidity

Why is the aquarium water quickly dimmed if the tank is equipped with a filter? The main problem is that on the very first day of the launch of the aquarium there is no holistic and permanent biological environment. The so-called "bacterial explosion" is caused by an active increase in the number of unicellular microorganisms that are constantly multiplying. In this case, the fish should not be settled, it is better to do it on another day. When microflora equilibrates in the tank, then the water will become crystal clear. Nothing serious needs to be done - this sediment will pass by itself. If you decide to change the water - it will again become muddy and unfit for life.

For 4-7 days the aquatic environment is fully restored, you can run plants and fish into it.To speed up the process, you can add water after the old aquarium with "residential" water.

Another common problem with the rapid turbidity of water in an aquarium is poor filtration of the reservoir. It should be well thought out system of purification, and this should be done quickly, until the young fish and did not have time to get used to a new house. A bad filter does not allow bits of dirt, feces, food debris, provoking the formation of decomposition products. Such rotten water constantly stinks and can cause diseases.

Watch a video about filtering water in an aquarium.

Why still water quickly becomes cloudy? If it has become an unpleasant green color, dimmed in a short time - it means that microscopic blue-green algae develop in it, which lead to the flowering of the reservoir. With good development of organic and strong light, they make themselves felt on the fifth day. When the light is not enough, cyanobacteria will acquire a brown color and begin to rot. Green color of the liquid with muddy, unpleasant smell - signs of growth of blue-green algae.

Aquarium water turbidity: action

If frequent water changes, the growth of bacteria and algae provoked the appearance of muddy water in the aquarium, some steps should be taken to eliminate the problem.

  1. If your aquarium is overpopulated, place the fish in different tanks, where they would be comfortable and spacious.
  2. If there is an excess of light, shade the aquarium by setting it in a secluded corner where strong lighting does not go.
  3. If the water becomes cloudy the next day after the first feeding, make a bottom siphon and feed the fish in small portions.
  4. Settle snails and fish in an aquarium that eat leftover food, clean glass and water in a tank. After a few days, the water will become free of dirt, and will not require additional replacement.

Wrong settlement of fish as a reason for the rapid turbidity of water

Why 2-3 days after the settlement of fish water became muddy? The fact is that for every one liter of water in the tank it is required to settle only one medium fish. If you run more pets, there will be problems with the pollution of the "house". Some fish plow the ground, and if there are many such individuals, it will turn into an underwater hurricane. Immediately move the fish in different aquariums, provide enough space for them. It is also important that they have enough oxygen, shelters and plants. In poor water oxygen to the fish can get sick.

In the aquarium with proper care and the right equipment, the water on the second day will not deteriorate. After running the fish, make sure that it adapts to the new environment. For 3 liters of water it is necessary to settle the fish size of 3-5 cm.

If the water is cloudy, you can use drugs that purify water from turbidity and dirt. After using them, water changes in the aquarium are not required for a few more days. They connect all the small particles that spoil the water until they fall into the filter. The next day, the entire bacterial cloud, small algae settle on the filter sponge, after which they can be removed.

These are the drugs: JBL Clearol, JBL Clynol, Seachem Clarity, Sera Aquaria Clear.

Watch a video about water changes.

How to change the aquarium water?

Full replacement of water is required only in the rarest cases, for example, with general quarantine or water poisoning. Why not do this procedure often? Because the day after the complete substitution, you will notice how the water turned cloudy again. A significant loss of its volume is stress for all inhabitants of the reservoir. Even during the death of some fish do not replace the water. But there are a number of recommendations, after studying which it is possible to understand why substitutions are necessary.

  • Substitutions are necessary after the introduction of pathogenic microorganisms;
  • Replacements are required after visible flowering of the reservoir;
  • Urgent water changes are necessary when a fungal mucus is detected;
  • Refresh water is required due to severe soil contamination.

You can add water to the tank as it evaporates, but not more than 20-30% of the total volume. It is best to update 1/5 of the aquarium once a week. After the procedure, the biocenosis will recover in 2 days. With the replacement of water cleaned the glass from plaque, remove debris from the bottom, clean snags and decorations.

It is better to plan a water change for both small and large reservoirs in advance. Type in a glass tank water from the tap, and leave it for a few days, covered with gauze. Chlorine and gas will evaporate, the liquid will be safe for fish. And it should be remembered that in the first week of operation of the aquarium the water is not changed until an ecosystem is formed in it.

Is it possible to completely change the water in the aquarium to a new one ??? And how to do it right ??? And how often? ...

Katyuvka Moskalenko

Completely water in the aquarium does not change! Do a partial water change of 20-25% every 2 weeks. But if you need to change all the water, then the recommendations are. For fish you need a spreader, respectively, a 3-liter jar is not suitable here, you need a volume for more. In the aquarium, add water from the tap, and some part of the old water. Filter, let it work (even without fish) in the sponge of the filter multiply the useful bacteria that are needed to maintain the biological balance in your tank, if it works, it will help to restore biobalance faster. And in general, wash out the sponge of the filter with water from the old aquarium, as the bacteria die in the running water and they will not have to multiply there when installed, you will take the ready ones. Water should settle for three days. But there are special preparations that contain ready-made bacteria, they will allow the fish to run a couple of minutes after the installation of the aquarium. But do a full restart only if you have a great need, and better follow the first recommendations, just do a regular water change, to maintain biological balance, then the water will always be clean and the fish will be intact and the mistress happy!)))

Ekaterina Mezentseva-Stolyarova

Depends on the volume of the aquarium.
There are 2 options:
1. You plant fish and rastyuchki in another aquarium, wash the old and pour H2O from the tap and wait until it settles, then rastyuchki and so on. VERY LONG.
2. Change to the already settled water, but leaving part of the old


the reason for such a radical replacement of water is not clear
when it is NECESSARY to replace all the water, pour out part of the old one, release the fish there and literally start the fresh separated tank (in the extreme case, boil and cool the sedimentary)
if in the aquarium the water is clouded, most often the opposite effect can be achieved by stopping feeding for two or three days.


This is called Aquarium Restart. It is done in exceptional cases, diseases for example. All residents are transplanted into a temporary house (second aquarium, bank, container ...) in the water which has settled for two days. At this time you wash the aquarium, everything that is there and fill in the water which has been settled for at least two days. It’s only clear that your biobalance will not recover soon after this procedure. And it is not known how the fish will carry this thing.
It is correct to replace 25-30 percent of water once a week, without touching the fish! And siphon the ground.

How often do you need to change the water goldfish?


Why do not write these neznayki! 25 liters for three gold, Natalia Bocharova, it is absolutely unacceptable! Aelita writes correctly - at least 50 liters for each. Next - goldfish emit mucus in the water, so changing the water and careful filtering, dear Zver - is required! Add water as it evaporates - this is really a sledgehammer on the head! ... it's the accumulation of salts in the water! Experienced aquarists do not lay gold in the ground at all - less turbidity. The only thing that is nice is that goldfish eat both bread and barley, and beef, ... generally, really piglets ...

Blind Drink

If the water is cloudy, you need to change. In general, I do not understand where the fashion came from to change the water 2 times a month, it's like a sledgehammer on the head with a sledge hammer. I only changed my own as a last resort, only topped up as it evaporated. And they felt great, were fruitful and multiplied.


Goldfish are piglets.
You do not need to change the water in the aquarium, but you need to change the water once a week. And whatever the water does not cloud, do not overfeed the fish. And for such fish you need a very good filter in the aquarium.
Plants are not necessary, they will still eat them.


This is a very small displacement. water will go out with terrible force. one goldfish needs 50 liters. You torture water to change. We need a very powerful filter with coal. Replacing water by 1/4 is needed weekly and do not overfeed. Completely all the water in the aquariums can not be changed and live plants are undesirable, the fish will be their jerk, and this is extra rubbish. It also requires high-quality food, from the cheap water also goes out

Natalia A.

I agree with Vladimir, scrofula need at least 50 liters per fish "face" with good blowing and filtration. Water in general does not change to fish, but they produce a partial substitution of 25-30% once a 7-10 days for a separated, scrofs in view of their "cleanliness" can be changed and a couple of times a week, they will thank you only.

How often do I need to change the water in the (small) aquarium "glass"

Natalia A.

A glass is good for wine, not for keeping water bionts! Even for a cockerel lung cancer, this is a punishment cell. Do not feel sorry for torturing the beast in the tank of the toilet? With proper care, water does not change, but is replaced = one third once a week.

Alexander Ognev

for one cock you need at least 10 liters. Imagine yourself in the toilet Khrushchev - here also feels like a cockerel. you still have to feed the fish with one dry food, which cannot be done.
the water does not change, but it is replaced by 30% of the volume once a week with a ground siphon.

Elizabeth Halliwell

The 3.5 Liter Aquarium is not a tank, but a can of water. There is no biobalance in it, and there is a complete confusion, both with care and for fish.
Aquariums are counted from 10l, 10-20l - these are nano-aquariums. For beginners from 30-40l is desirable
A heating pad is obligatory for a rooster, a filter too (filter is the heart of the aquarium).
Study the content, feeding, care, etc.
in this volume I will change 1/4 part every day for separated water for 2-3 days, + every time a siphon of the bottom is siphoned (can be made home-made for such a volume from an IV)