How to Move Fish from One Aquarium to Another?

Fish don’t adjust to new environments easily. That is why you need to move them from one aquarium to another with care.

Make sure that the temperature and pH levels are the same in their old and new environments.

Also, take care of the ammonia levels by using old filters and other equipment. Your new aquarium has to be set up completely before you introduce your fish to it.

Here is a guide on how to make this transition comfortable and safe for your fish.

Clean New Equipment before Use

If you’re using new equipment, rinse everything once before it goes into the aquarium.

This will prevent any chemicals or debris from packing getting into the water. It is a good safety measure for keeping your fish from harm’s way.

However, in most cases, people use equipment from their old aquariums. This includes filter media, gravel, and decoration pieces.

It’s good to use old equipment because it has beneficial bacteria populated over it. This can make the transition to the new aquarium easier.

Remove Your Fish from the Old Aquarium

Use a siphon to drain the water from your old tank into a clean bucket. Ensure that your bucket has no remnants of soap in it.

Your fish will go into this bucket temporarily so it’s best to be safe. Chemicals like soap can be toxic for your fish and can cause illnesses.

Once there is enough water in the bucket, use a fish net to scoop your fish out of the aquarium. Keep both of your hands wet with the aquarium water.

This will prevent exposing it to a dry surface if it comes in contact with your hand.

Gently rest your hand over the fish when you get it into the net. You can avoid it from jumping out of the net this way.

Transfer the fish into the bucket as soon as it gets in the net. The less time your fish is outside out of the water, the better.

Related read: How to Catch Aquarium Fish without a Net

Set Up Your New Aquarium

You have to ensure that the water in the aquarium is suitable for your fish to live in.

Most importantly, you will have watched over the ammonia levels in the water.

Add Water to the Aquarium

You can either use some of the water from the old aquarium or none at all. Add some of the water you siphoned off from the old aquarium into the new one.

Try and avoid letting any visible dirt from getting into the new aquarium. It’s best for your fish to be transferred into an aquarium that has mostly clean water.

This will prevent all of the waste in the previous water from getting into the new one.

You can choose to use some of the water from your old aquarium. It can be a safe way to manage the water’s ammonia and nitrate levels.

However, do not use much of it. About one-third should be more than enough for your new aquarium.

You don’t want the dirt and waste in it to get into your new aquarium.

Add clean tap water to top off the aquarium for your freshwater fish.

New water also helps you regulate the amount of ammonia in the aquarium.

That said, a new environment can be stressful for fish. Thus, you don’t have to add all of the water at once. You can gradually bring it up, even after your fish are in the water.

Related read: Can Distilled Water Be Used in a Saltwater Aquarium?

Match the New Water’s Temperature and pH Levels with the Old

Ensure that the temperature of the clean water you add matches that of the old aquarium. An increase or decrease in temperature can stress your fish.

Greater or lower pH levels can be harmful to your fish’s health. You can get an inexpensive aquarium thermometer to check the temperature.

Get pH tests from the market to monitor your water at the time of the switch and after.

Set your heater to the same setting when you put it in your new aquarium. Let it stay on for about a few hours to let the water reach the correct temperature.

Don’t rush to put your fish in the new aquarium. Water changes temperature relatively slow.

This means that one part of the water may be the correct temperature, but another may be colder.

Use Your Old Filter to Stabilize the Water in the New Aquarium

You must begin a nitrogen cycling process in your new aquarium.

This process creates a healthy environment for fish by removing ammonia with good bacteria. The production of bacteria is slow and cycling your aquarium can take weeks.

However, speed this process up by using your old filter from the previous aquarium. Use your old filter along with the new one for the first few weeks. Your old filter media has good bacteria colonized in it.

It will disperse beneficial bacteria in the water. This helps make the water stable and safe for your fish.

Begin the filtration in the new aquarium sometime before you put your fish in.

You can remove the old filter after a few weeks. The water will be stable by then, and the good bacteria from your old filter won’t be necessary. The new one will take that role on by then.

Don’t Rinse the Paraphernalia from Your Old Aquarium

This beneficial bacterium also colonizes over hard surfaces in the aquarium.

This includes rocks, gravel, and decoration pieces as well. Add these without rinsing them to the new aquarium.

It will help regulate the new aquarium’s environment. This way, you can put your fish into a new and safe environment quickly.

Putting your fish into an aquarium that isn’t cycled can be fatal for them. There won’t be any good bacteria (nitrate) in the water to counteract the ammonia levels.

Place Your Fish in the New Aquarium at the End

Have everything in your aquarium ready before you put your fish in there. It is your last step and the water should be perfect for them before you complete the switch.

Transfer your fish into the new aquarium directly if the water temperature and pH levels match the old one.

Use your net to move them from the bucket to the aquarium.

As mentioned earlier, place your hand gently over the net to stop your fish from jumping out. It can get injured if it falls onto the floor from a height.

Don’t force your fish out of the net when you introduce them to the new tank. Submerge the net into the water along with the fish in it.

Keep it there until the fish swims out of it on its own. Allow it to find its own way into its new home.

Don’t put your fish in the aquarium directly if there’s a discrepancy in temperature and pH levels.

Both must be the same as in the water of your old aquarium. This will ensure that the fish are comfortable in their new environment.

If the water doesn’t match, perform the process you would when you buy a new fish. Use a fish bag to make the transfer.

Hold the bag full of the old water on the surface of the new aquarium’s water.

Gradually add about 25% of the new aquarium’s water into the bag. Keep adding water after a few minutes so that the bag is nearly full.

Your fish can then get into the water in the aquarium. This process helps the fish get used to its new environment with ease.

Things to Take Care of After You Make the Switch

Keep an eye on the water even after you move your fish to the new aquarium. It takes time for the water’s ammonia and nitrate levels to stabilize.

Keep adding fresh water into the aquarium to help stabilize the environment. You should check the water daily to prevent any harm to your fish.

Reduce Ammonia Buildup through Feeding Habits

Fish’s waste is the main cause of excessive ammonia buildup in your aquarium. In the first few weeks, you can control this by how much you feed your fish.

Feed them significantly lesser than you normally do. This will reduce the amount of waste they release into the water.

Fish can go without food for about a week, so it is safe to feed sparingly. Do that to allow the beneficial bacteria from the old filter and the decorations to colonize the new filter.

This will allow your fish a more gradual transition into their new environment.

Perform Daily Checks for Temperature and pH Levels

Use your aquarium thermometer to check if your heater is functioning properly. There should be little to no change in temperature each day.

You can also test your new heater this way too. If it is faulty, use your old one as a backup until you replace the new one.

Regulating pH levels can be tricky. If there is much change after a few days or weeks, you may have to remove your fish temporarily. Baking soda is good for increasing the pH if it is too acidic.

On the other hand, peat moss works well for lowering the pH level in the aquarium. Put your fish back in the water after you make the change.

Whatever you do, don’t make sudden changes. Doing so will severely harm your fish.

Allow a gradual change so that they can comfortably adjust to the new environment.

Do Your Research Before You Make the Switch

Do your research before buying a new aquarium. You want to be sure that the new one is the right size for the environment.

This is more important if you’re getting a smaller aquarium because of a lack of space.

Your fish need enough room to be comfortable, especially if you have a lot of them.

Last Few Words

Moving your fish into a new aquarium can be a risky process. Fish are sensitive to change. Some can cause stress and others can be physically harmful or fatal.

You must ensure that you carry out the process with care. Carefully perform each step, and avoiding rushing your fish into their new environment.

Try and make the water as similar as possible to the one they were in. This will ensure that your fish have a smooth transition.

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