Coming home with a new fish purchase is always exciting. However, most people are concerned with how the fish will acclimate to its new environment. Will it survive? Will it stay healthy? Or will it inflict the other inhabitants with sickness? Here are some steps to ensure the introduction of your fish is as healthy and happy as possible.
1) Perform a water change before adding new fish. For water change recommendations, see Disease Prevention Tips. Wait 24 hours for the water chemistry to stabilize.
2) Test the water chemistry and record the findings. Take a sample of water to the local pet store and have them test it. Ideally, the sample container should be glass, clean and dry before introducing the water sample. The readings should be the same or very close to each other. This will show the pet store that they are selling a fish to an acceptable aquatic environment. It is necessary in new setups that the system “cycles” before adding ornamental fish. This process is typically a month to 1.5 month long process.
3) Have the pet store test their aquarium water that holds the fish of interest. Key components to compare between the two test samples are:
- nitrate, and
If a pet store won’t allow this comparison, then go find a new pet store. I would worry, this type of store is not entirely honest about the health of their aquarium water or the fish. If the comparison checks out, then purchase the fish. If not, use caution, the comparison doesn’t have to be 100% but if any ammonia or nitrite show up, or the pH differs significantly, do not buy the fish!
4) Float the fish bag in the new aquatic environment for 10 to 15 minutes. This will ensure the temperature of the water in the bag will be the same as the temperature in the new aquatic setup. Keep in mind, fish find acclimation much easier if the temperature adjustment is only several degrees different.
5) Open the bag and discard one quarter to half of the water from the bag. When it comes to saltwater acclimation I would remove the smaller amount of water recommended. I use a turkey baster or pour directly into a measuring cup. Then replace the discarded water with water from the new aquatic environment. Close up the bag again. Wait 10 to 15 minutes. The key to this step is to give the new fish a subtle acclimation to any water chemistry differences between the new water environment and the pet store water.
6) Perform step 5 one to two more times and again wait 10 to 15 minutes in between each water exchange. It is recommended to perform the repeat of this step more often when acclimating saltwater fish.
7) Using a straining device, preferably a fish net with fine mesh, separate the fish from the water in the bag. Gently release the fish into your aquarium and observe. Discard this water. The key to this type of release is to ensure the least amount of cross contamination from the pet store’s water. Continue to observe your new fish intently for the next few days to ensure a comfortable transition has occurred.
8) It is also recommended not to feed newly introduced fish, typically they will not eat right away after initial acclimation. Also, the newly introduced fish can be stressed and eating during this period can make it ill.
When acclimating fish, I like the Hagen Marina nets and make sure they state “soft net” or “fine mesh”. This type of net is not excessively abrasive and will not remove large amounts of the fish’s slime coating during the acclimation. Remember, the slime coating on a fish is its primary immune system. Also you will find a link to Kordon’s slime coating replenishing liquid to add to the aquarium after the new fish have been introduced. This is a quality product I have used during my entire time in the aquarium maintenance business and it also serves as a great dechlorinating additive.