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Do Freshwater Fish Like & Enjoy Water Changes? Answered

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Water changes are necessary for owning aquariums, but they can be a hassle. However, the benefits outweigh this hassle and will keep your tank nice and clean.

Freshwater fish do not experience emotions such as happiness, however, they tend to be more active after a partial water change. This can lead us to think that freshwater fish do like and enjoy water changes as long as they are done properly. If not done properly, it can cause shock and death.

With that being said, it is important to know when to do a partial water change, how to complete the process, what products you need, and more!

Active and Hyperactive Fish

Active Fish

After a partial water change, you may notice that your fish are a bit more active. This can mean one of two things: they are either content with the water change or they are in shock. Both of these statements are on two very different ends of the spectrum and it can be difficult to know what is going on in the tank. 

It is a good sign if you completed a partial water change and see that your fish are swimming a bit more and exploring everything; particularly if you had a lot of debris in your tank. During my water changes, I also move around the decorations in the tank to give the fish a new environment. This means that your fish are content.

Bleeding Heart Tetra Hyphessobrycon Eryhrostigma aquarium fish

Hyperactive Fish

However, it is not a good sign if you notice that your fish are hyperactive. Hyperactivity includes all of your fish swimming sporadically or having the “zoomies” as you would see in dogs. You may also notice that your fish are heading to the top of the tank gasping for air, or are lethargic at the bottom of the tank. 

The above signs can mean that your fish are under immense stress from the water change and it was not done correctly (usually a full water change). Another word for this is an osmotic shock. 

Fish use osmoregulation to have the correct amount of fluid in their bodies. If they are in shock it means that the fish are unable to regulate the compounds in the tank which led to too much absorption of water or a high release of fluid. They will then swim erratically (a condition called dropsy) and can potentially die rather quickly.

Partial Water Change

To avoid your fish getting stressed and being hyperactive, you will want to make sure you complete partial water changes and not full water changes unless necessary. A full water change should only be done if there is a disease wreaking havoc on your tank that cannot be cured.


With that being said, it is recommended to do a partial water change once a week on your tank. If you have a larger tank, you can get away with doing a water change every other week. A partial water change entails replacing about 5-10% of the water in the tank.

By replacing only small amounts of water at a time, you are ensuring that there will not be a drastic water temperature change that can kill your fish. This also means that good bacteria will be left in the tank which is beneficial to fish and plant life.

Cleaning the Tank

When completing the partial water change, you will want to also clean the bottom of the tank with a gravel cleaner to remove any excess waste and toxins. This will keep your tank parameters in check and keep your fish healthy. 

You can also remove any decorations in the tank and rinse them off with dechlorinated water. Remember to never put tap water in your tank directly unless using a dechlorinating chemical. You can also scrape the aquarium glass to remove any excess algae. 

How to Save a Dying Fish After a Water Change

If you notice hyperactive behavior in your fish after a water change there is a good possibility that it may die. However, if you take prompt action you may be able to avoid this, but there is, unfortunately, no guarantee.

  • Move the fish to a tank with the correct parameters. Since your fish is already stressed it may be too late to save him/her but changing tanks is worth a shot. If you have a cycled spare tank, you can try placing the fish in the new tank and see if it helps. 
  • Add bacteria-starting supplement. When trying to cycle a new tank quickly, many people will buy a solution at a local pet store or online that contains beneficial bacteria to start the cycle. You can use this same solution to add bacteria to your tank that may have been lost in a full water change. If you add the solution slowly, you may start to see an improvement in the behavior of your fish which may be able to pull them out of their shock.
  • Use a bubbler or air stone. When fish are in shock, their level of oxygen decreases. In order to add oxygen quickly to the tank, you can add a few air stones or a bubbler wand. Both will add bubbles to the water immediately which increases the oxygen.

What to Do if a Fish Dies in the Tank

If you do happen to lose a fish due to a water change, you will want to remove the fish immediately. Fish start decaying right after death, so the toxins can cause other fish to pass as well. 

You will then want to test the parameters of your tank using test strips to ensure the dead fish did not change the levels of nitrates, pH, and ammonia. If the levels are off, you will want to fix the problem quickly with chemicals.

Usually, you would do a full water change, however, if the parameters are corrected quickly this is not necessary. Another water change could shock the remaining fish again and cause even more problems. You will want to test the parameters more frequently until all parameters are in check and the other fish appear healthy. 

Tips for a Positive Water Change

It is important to note that your fish should not be stressed after a water change and they should be content with the change. To avoid stress we mentioned doing partial water changes, however, there are a few other tricks you can do as well to make it as less stressful as possible for your fish. 

  • Keep the temperature in check. If you are doing a partial water change, it is imperative to try to keep the new water at the same temperature as the old water. This will keep the fish from getting shocked. Also, keep in mind that tropical fish are more sensitive to temperature changes.
  • Use a dechlorinator with aloe. There are several different dechlorination chemicals on the market for fish tanks, however, I have found that the best ones include aloe. The aloe coats the fish which makes them less susceptible to experiencing a shock. 
  • Only rinse or change the filter a few days after doing a water change. When doing any water change, you are bound to remove some of the good bacteria from the tank. To avoid removing more of the good bacteria, you can wait to clean the filter for a few days after doing the water change. This will allow more water to cycle through at a constant rate and will reduce shock.