We need to be concerned about more than just temperature. The aquarium water chemistry is just as important as the temperature when it comes to acclimating fish.
Don’t be afraid to ask the fish clerk for store’s tank pH, ammonia, nitrite and nitrate readings. When you get home, test your own water to see how much the two sets of results differ. This can provide you with some insight into how slowly and for how long you should acclimate your fish.
There are a few different recommended methods for how to acclimate fish to your aquarium and we’ll talk about each of these methods.
The most common tropical fish acclimation methods are:
This is probably the most common fish acclimation method and it works well. You just need to be careful when floating a bag full of unknown water in your tank.
After you leave the fish store you will want to go straight home to avoid ammonia accumulating in the bag (in the form of fish waste). Once you get home, open the top of the bag and remove about 25% of the water from the bag. Replace this water with the same amount of water from your tank. Float the bag in your tank and bring down the hood opening on the open end of the bag to help keep the bag secure. Every 10 minutes add about 1 measuring cup (use less if the bag is smaller) of your tank water to the bag. Repeat this process for about an hour. After an hour has passed use a small net to get the fish out of the bag and gently place the fish into your tank. The main idea here is to slowly get the fish used to your tank water (acclimated). Do not dump the bag water into your tank! If you do, you risk exposing your tank to any parasites or diseases that were in the dealer’s tanks.
Some fish may be difficult to net while in the bag and you don’t want to damage the fish while trying to net them. If you’re having difficulty netting the fish, get a large bowl (large salad bowl works well) and carefully pour the bag water into the net, allowing the bowl to catch the water. You could bypass the bowl altogether and do it over a sink but make sure that the drain plug is in place just in case you miss the fish with the net. By slowly adding small amounts of water from the tank we are slowly acclimating the fish.
This fish acclimation method is basically the same as the floating bag method, but instead of floating the bag in the tank you’re putting the bag inside a clean bucket instead. The bucket method is better than the floating bag method because you don’t have to worry about any of the bag water entering your tank.
Open the top of the bag and remove about 25% of the water from the bag. Replace this water with the same amount of water from your tank. Every 10 minutes add about 1 measuring cup of water to the bag. Repeat this process for about an hour. After an hour has passed use a small net to get the fish out of the bag and gently place the fish into your tank.
Acclimating new fish to your aquarium is a critical step and should not be taken lightly. Getting into the habit of using proper acclimation methods is a good way to ensure your long-term success in this wonderful hobby!