Last Updated: 3/6/07

This page discusses how to acclimate and add fish and other aquatic animals to aquariums or ponds.

Floating the Bag
Acclimation

I wrote this page off the top of my head on 2/9/07.

The standard old method to add fish to your tank or pond goes as follows, "Yeah, float the bag in the tank (or pond) for about 20 minutes and then let the fish go." Here are a list of pros and cons for that method.

Pros:

• The temperature should equilibrate in that time so, when you add the fish, it should not get temperature shock.
  
• The new and old fish or other animals get to see each other and have a short preview of their meeting which can reduce chasing, etc. when they are put together.

Cons:

• This method does absolutely nothing to prepare the fish for a change in water chemistry. If the tank/pond water has a different pH, hardness, and/or other chemical parameters, the fish can go into shock from that when released. If possible, it would ideal to be able to test at least the pH levels of both the tank/pond water and the store water for comparison.
  
• Adding water from the store could introduce things such as high ammonia, wastes, or even diseases, parasites, snails, etc.
  
• While waiting in the bag there floating, the fish or animal is in water that probably now has low oxygen levels, high ammonia levels, and is generally not that good.

So, what to do? First, never add store water to your tank or pond. After floating the bag (if you do that), pour the fish into a net and add just the fish or other animal to the tank/pond. Second, it is better to acclimate the fish to your tank or pond water. See the next section for how to do that.

To acclimate fish or other animals to an aquarium or pond, there are a few options. The simplest is to gently pour the new animals into a "fish-only" bucket with the store water. Then, add from the tank or pond, water equal to about half of the store water volume. Now, the fish is in two- thirds store water and a third of the new tank/pond water. See how the fish reacts. If it is not jumping around, it is probably ok. After about 10 minutes, add in another portion of your tank/pond water. Be sure to cover the bucket once the volume is enough that the fish could jump out. Once the fish is in around 75%+ tank/pond water and 25% store water and seems fine, then net the fish out into the tank/pond. For tanks, do not forget to top off the main tank (because you removed some water) and include dechlorinator and aquarium salt (if you use that; a dose for the volume removed). If this is for a pond, the amount of water is probably not significant to require replacement.

It is preferably to use a quarantine tank or pond for new fish but that is not always possible. You may want to soak the net and bucket you used in some dilute bleach for a few hours followed by fresh water with dechlorinator for a few hours to sterilize it. Keep an eye on the new animals for a while to be sure they are okay. They should be used to your water from the acclimation but they now will have to deal with any other animals already in the tank or pond. It is normal for established fish to chase the new fish. If this involves biting or actual injury, the new fish should be removed at least until things calm down. It is not fair to punish your established fish for normal behavior (if it is normal). In tanks, fish can also be separated with tank dividers or net breeders temporarily.

Another more complex method of acclimation is put the fish into a larger tank and put in a drip line that very slowly drips the tank/pond water into the tank. This very slowly lets the fish get used to your water. This is most often done for expensive fish going into large tanks or ponds. Very slow acclimation is ideal.

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