Acclimating New Fish to your Tank

Buying a new fish is an exciting day. You’ll be one step closer to completing your tank or replacing a fallen comrade.

Fish that you buy have been living in an environment that is likely different from your water in some way. It can be unsafe and unhealthy for your new fish to just add it directly to your tank without acclimating it.

When acclimating new fish to your tank, you slowly change the environment of your new fish from its old water parameters to the parameters of your tank. This helps to ease the stress and minimize the shock on your new tank mate.

16toki [Public domain]
16toki [Public domain]

Why Do I Need to Acclimate your Fish

The New Fish

Your new fish has spent his time living in the local fish shop’s water. That’s its home. That’s what its used to. It’s has had time to adjust to the water parameters – temperature, ph, salinity, etc.

You can’t just take a fish out of the water its used to and drop it into a completely new set of water parameters without it experiencing shock and stress.

We acclimate to slowly transition the fish’s existing water parameters to those of our new tank.

This helps to ease stress and will help to keep your fish healthy during an already stressful time.

Your Existing Fish

Your existing fish also need time to transition. While they don’t have to deal with the stress from the water parameters, they are soon going to have to figure out where this new tank mate fits into the tank.

Your existing fish know where they stand with other tankmates. They know who are their “friends” and who to avoid. They have their territory and the places they like to hang out.

This new fish is going to completely uproot all of this.

Float Method for Fish Acclimation

With the float method, you put the still sealed bag with your new fish into your aquarium water. Then open it up and slowly add in small amounts of your aquarium water into the bag. After a while, you’ll scoop out your new fish from the bag and put them into your aquarium.

Float Method Steps

Turn off the light in your aquarium. This will help to lower the the stress level in the fish, both already in your tank and your new fish.

Rinse off the outside of the bag with tap water. Pat it dry then put the still closed bag into your tank. This helps to slowly transition the temperature of the water in the bag to the temperature of your tank.

After 20-30 minutes, remove the bag from your aquarium and remove the tie from the top. Dump out about half of the water from the bag. Put the bag back into your aquarium making sure not to let any water from the bag into the aquarium. Take a small amount of water from your tank and add it to the bag.

You will want to set up a rig to allow you to leave this bag, still opened, in the tank without you holding it. I personally like to put the top of the bag outside of the top and then close the lid on it, but there are several options here. Figure out what works for you.

Every 5 minutes, you should add a small amount of water from your tank to the bag. Continue this until you’ve doubled the volume of the bag.

Your fish is now ready to move to your tank. Using your fish net, remove the fish from the bag and slowly lower it into your tank. Let the fish swim out of the tank on its own. Congratulations! You’ve added a fish to your tank.

It’s important to note that you should not let any water from the bag into your tank. The water from a fish store is often riddled with disease which you can introduce into your tank.

The Drip Method

The drip method is usually the choice of advanced fish keepers. The spirit of the drip method is the same as the float method. You’ll be slowly adding water from your tank to the water in the bag with your new fish. This lets your new pet slowly get used to the water in your tank without a big shock. The drip method is just as it sounds. You slowly drip water from your tank into the water with your new fish.

Drip Method Steps

Turn off the light in your aquarium and run airline tubing from your tank to a bucket.

Tie a knot in the tubing or use a control valve.  This will be used to limit the flow of your siphon.

Start a siphon into a bucket and adjust the “tightness” of your knot or the flow of your control valve.  It should be dripping at 1-2 drops per second.  Put the now dripping end into the fish bag and let it sit for about 30 minutes.  This will slowly and consistently adjust the water parameters around your new fish.

After 30 minutes, your fish is now ready for your tank.

Take your net and scoop out the fish.  Do not dump water from the bag into your tank.  This can transfer disease from the fish tanks to your tank.

Put the fish into your tank and your new fish is now in its new home!

Common Acclimation Problems

Going too Fast

It’s not a race. You can’t speed up the process. The times we listed above are minimums. Don’t go shorter than this, but feel free to go longer.

Existing Fish Not Tolerating New Fish

Fish are wild animals and sometimes they just don’t get along right away. You should pay very close attention to how everyone is behaving for the first couple of hours. Keep an eye on them beyond that time frame, but the first couple of hours is very telling.

If you notice your new fish being bullied or bullying, you should isolate him from the rest of the tank using a tank divider, breeding box, or something similar.

Give it them some time separated to get used to everyone’s presence. Then you can try again several hours to several days later. If you still see signs of aggression, repeat the above steps.