New Fish Acclimation in 3 Easy Steps

August 28, 2018 0

Fish acclimation is the process to give fish enough time to adapt to a new environment through incremental changes.  If acclimated well, most fish can adapt to the water in any new fish tank without a problem.

Acclimation is mandatory when you bring home any new fish.  It is because fish can die rather quickly when there is a big difference in water parameters.

A sudden change in the water temperature, PH, hardness, dissolved oxygen level, and even nitrate concentration might stress, shock, or even kill the new fish.  It is one of the top reasons a lot of new fish died soon after they got home.

The keyword here is “sudden.”  Most fish can adapt to more gradual changes.  It must be incremental, and we must give the fish plenty of time to get used to it.

Before Start Acclimating Fish

You must have a full setup of an aquarium with all the essential equipment in place.  The water temperature must be right.  It must have aquarium water conditioner in it if the source of water is from a tap.  The aquarium filter must be fully cycled for aquarium nitrogen cycle.  Otherwise, you are not ready to bring fish home just yet.  If you ignore the advice, your fish will still die even if you acclimate them.

If you have a lot of fish in your home aquarium already, it is highly recommended to settle the new fish in a quarantine tank instead of your main tank.  Countless contagious fish diseases and parasites are out there.  You do not want any of it in your established aquarium.  You can skip the quarantine tank if you have no fish in the fish tank.  The whole idea is to separate the new fish from the fish you already have.

Tools for Fish acclimation

To acclimate fish to a new fish tank, we will need to keep the fish in the plastic bag they came in with.  Ideally, a plastic fish container works better since we can hang it on the side of a fish tank.

New Fish Acclimation in a fish container hanging on the side of the fish tank.
We also need a large fishnet for the final moving.

A water bucket will come in handy as well.

Fish Tank Water Temperature Before Fish Acclimation

Even as fish can adapt to a wide range of water parameters, the water temperature should not too far off from their natural habitat.  Make sure the water temperature in the fish tank is within the acceptable zone for the particular fish species.  Adjust the aquarium heater accordingly to get the ideal temperature before you get started with the acclimation.

Three Steps for Fish Acclimation

  • Fish acclimation for water temperature

The water in your home aquarium might have very different temperature compared to the water in the plastic bag the fish came in with.  Water temperature difference is the first thing the fish must get used to.

Therefore, the first thing we must do is to set the plastic fish bag in the fish tank for around 20 minutes.  If you have the fish container, dump the fish and the water from the plastic bag into the container.  Then hang the fish container on the inside of the tank.  Make sure at least half of the fish container is in the fish tank water.  It is important not to let the water from the plastic bag come in contact with the fish tank water.

After 15 to 20 minutes, the water temperature in the plastic container should be around the same as the water in the fish tank.

A lot of fish beginners know this step, as the fish stores often recommend this part.  However, most fish stores only recommend this step and no further.  It is crucial to know that the water temperature is not the only thing the fish must adapt to before we set them free in the tank.

  • Fish acclimation for other water parameters (PH, hardness, nitration concentration, etc.)

After the water temperature is similar, the next thing to do is to replace around 25% of the water from the fish container with the water from the fish tank.  Do not let any water from the container into the fish tank.  Discard it.  It is when the water bucket comes in.

Wait for another 20 minutes for the fish to get used to the changes in water.

Then replace another 25% of the water in the fish container with the water from the fish tank.

Repeat the same process every 20 minutes.  Until almost all of the water in the fish container is from the fish tank.  It can take two to three hours in total.

Alternatively, after the first hour of 3x 25% replacements, you may increase the replaced water to 50% every 20 minutes.  Since the first a few changes in the water parameter had the biggest impact, it is essential to keep the percentage changed small.  The later changes can be up to 50% each time without a problem, and it will speed up the acclimation process.

If you are replacing 25% water every 20 minutes all the way, it can take 3 hours to finish.

If you use the alternative method, you can finish it in 2 hours.

For more sensitive fish, you might want to stick to the first method for a more gradual and longer acclimation process.

By the end of the 2~3 hours, the fish should have already adapted to the new water parameter in the fish tank.  They are ready to settle in.

  • Move the fish into the fish tank.

Take a large fishnet and hold it directly above the water bucket.  Dump everything from the fish container into the fishnet.  The water will go through the fishnet into the bucket, while the fish will all be in the fishnet.  Take some water from the fish tank with the fish container or any other clean water container.  Use the water from the tank to wash the fish in the fishnet by dumping them on the fish from close distance over the bucket.  This step must be quick.  Or the fish can’t hold their breath any longer.

Once it is complete, take the fishnet to the fish tank and put it in the water.  Let the fish swim out of the fishnet on their own.

Observe the fish after the acclamation

Some fish might be weak due to inadequate care at the fish farms, or the stress from the transportation.  Even if you have done everything right, there is still the possibility a few new fish might not make it.  It is the best to keep eyes on the new fish after they have settled in.  So you will notice it right away if there is anything out of the ordinary.  Do not rush to feed them just yet.  Give them 24 hours to get used to the new home before a small feeding.  New fish might be nervous in a new fish tank.  Especially after the transportation and the fish acclimation process.  They will most likely ignore the fish food if you feed them too soon.  Uneaten food will be a waste and pollution in the water.