How Often to Change Goldfish Water?

Most goldfish owners know they need to change the aquarium water at regular intervals. However, many of them are not sure what frequency of water changes is right for their fishy pet.

So, how often should you change your goldfish water? Unfortunately, there is no general answer to that question. In fact, the right frequency depends on your tank size, and fish-to-water ratio. However, the de-facto norm is to change around 15% of the tank water every week. Remember, however, that you might require increasing the frequency in some situations.

For instance, if you did not cycle your tank water before adding fish to it, you should change the water twice a week or even daily. So, the frequency depends on many factors. Hopefully, this article will answer all your related questions, including when to change the water, why it is necessary, how much to change, etc. So, let’s dig deeper into the topic of goldfish tank water changes.

Why do you need to change your goldfish tank water regularly?

Broadly speaking, regular water changes do two things. First of all, it helps reduce or control the nitrate level in your aquarium water. Secondly, it helps replace and replenish the essential minerals in your tank water. In addition, making regular water changes is a great way to remove any uneaten food particles and the urine and feces of the fish from the water. Eventually, the whole purpose of making water changes is to keep your fish in good quality water. 

Why is it necessary to keep the nitrate level low?

Perhaps, you already know that too much ammonia (NH3 and NH4+) or nitrite (NO2) is harmful to your goldfish. Hence, experts recommend that you should establish a proper nitrogen cycle in your tank water before adding any fish to it. Essentially, cycling helps convert the harmful components (ammonia and nitrite) to the less harmful nitrate (NO3). However, just because nitrate is less reactive doesn’t mean it does not harm your fish. In fact, excessive nitrate levels could result in nitrate poisoning, which may even kill your fish. So, it is important to keep the nitrate level in control. Thankfully, regular water changes help remove nitrates from the water.

How does water changes help replenish minerals?

Typically, minerals like calcium and magnesium play a major role in the process of buffering. So, buffering is a process, in which the minerals help neutralize the nitrite or nitric acid in the water. However, mineral content in the water reduces over time. So, if you don’t change the tank water regularly, the minerals either are used up or settle to the bottom of the tank. As a result, your tank water loses the ability to neutralize the nitric acid, which often leads to nitrate poisoning in the tank. So, you should replace the water in your goldfish tank regularly. New water brings with it new, fresh mineral content necessary to keep the water’s pH level in optimum level.

Do goldfish like dirty water?

Goldfish are notorious for producing a lot of waste materials. As a result, they pollute their aquarium water faster than most other fish species do. Interestingly, the messy nature of goldfish has led many people to believe that goldfish like dirty water. However, that’s not true. On the contrary, goldfish like living in clean water. In fact, the lack of oxygen in dirty water can make your fish sick. Typically, goldfish release a lot of ammonia to the tank water. So, if you don’t clean the tank water regularly, the ammonia buildup could even poison your goldfish.

Can you use topping off as an alternative to water changes?

First of all, let’s understand what topping-off actually means.  Simply put, it refers to the process of adding fresh water to the tank. The purpose of topping off is to replenish the evaporated water in your goldfish tank. So, it doesn’t change the existing water but only adds fresh water to the tank. In fact, when water evaporates out of your tank, it doesn’t remove any waste materials from the tank. All the nitrates, minerals or fish wastes still remain in the tank water. So, if you keep adding fresh water from the top, it doesn’t help purify the water. Suffice to say, topping off doesn’t meet the need for making regular water changes.

Will a full water change kill my fish?

Ideally, you should change a certain percentage of the tank water every week. For instance, you can change 30% of the water weekly. If you conduct 100% water change, it could stress or even kill your fish. In fact, a complete or massive water change means that it would suddenly change the water chemistry. Eventually, your fish might fail to adapt to the drastic shift in water chemistry. As a result, some fish can die, while others may get ill.

How to do a partial water change

Firstly, keep all the necessary tools handy before you start doing a partial water change. For instance, you need an aquarium vacuum, a bucket and a water conditioner product for treating the tap water. First things first, unplug any external and internal equipment attached to the tank. For instance, unplug the water filter. Secondly, place the suction end of your vacuum to the bottom of your water tank, preferably into the gravel. At the same time, place the vacuum hose’s other end into the empty bucket. Now start the vacuuming and move the vacuum’s suction end around the gravel to pull out most of the dirt. Finally, add fresh water to the tank. However, make sure you treat the fresh water with a water conditioner before adding it to the fish tank.

How long should you allow the water conditioner to sit?

Typically, letting the treated tap water to sit for 20 to 30 minutes should suffice. Notice, however, that this formula is applicable only to “treated” water. If, however, you choose to use untreated water (not recommended), you should let the water sit for at least 24 hours before adding it to the goldfish tank. So, the purpose of using a water conditioner for treating tap water is to remove the chlorine and chloramines from tap water. Usually, a good conditioner doesn’t take more than 30 minutes to get rid of the chlorine and chloramines. So, it is enough to allow the treated water to sit for 30 minutes before adding it to the fish tank.

Should you remove your goldfish from the tank when doing a water change?

In general, you do not need to remove all your goldfish before doing a partial water change. However, if you are doing a total or massive water change, consider placing your fish in a temporary tank. So, it really depends on how much water you are planning to change. Ideally, you should never empty your tank completely. In some situations, however, you may need to go for a total tank cleaning. For instance, if you notice your fish getting sick repeatedly, your tank water environment perhaps needs a complete overhaul.

Why you should not wash your tank filter in tap water?

Essentially, not all bacteria are bad for your goldfish. Granted, most bacteria are harmful for your fish, but you also have some good bacteria. So, good bacteria usually live insider the filter sponges and the rocks at the bottom of your tank. However, if you clean the filter and gravel of your tank with tap water, it could remove all the good bacteria from your tank. Alternatively, consider using your existing tank water for cleaning the filter, gravels and air pump.

Why does my goldfish tank get cloudy so fast?

Actually, a goldfish tank can get cloudy for many different reasons. For instance, excessive buildup of heavy metals and minerals such as phosphates could make your tank water could look cloudy. Another cause could be excessive algae growth. So, if you want to solve the problem permanently, you first need to detect the root cause. In general, if the water looks green, excessive algae growth is the cause. On the other hand, if the cloudy water looks white, it could be due to a bacterial bloom.

How much water should you change each week?

Firstly, you should consider the fish-to-water ratio in your goldfish tank. However, it is not the only factor to consider. The size of your fish or fish tank is also an important consideration. Usually, you should keep a maximum of 2 fish per 20 gallons of water. However, if the size of your goldfish is between 2 to 3 inches, you can keep 3 or 4 fish per 20 gallons of water. Typically, a heavily-stocked aquarium needs to change around 25% of the water every week. On the other hand, a lightly-stocked tank should conduct around 15% water change every week.

How to keep the tank water clean?

In addition to weekly water changing exercise, you can plant EcoBio stone into the water to absorb impurities. Made with natural volcanic rock, EcoBio stones are fertile with live bacteria and nutrients. Usually, the stone lasts up to 2 years.