There are several steps that need to be taken to ensure the successful transfer of a new fish from your local pet store to your home aquarium. Ideally you should be placing the new fish in a quarantine aquarium, but most of us do not. The idea of acclimation is to avoid unnecessary shocks to the new fish. This can greatly reduce the chance of a new disease or parasite outbreak. 

It is best to do the acclimation under low light conditions to help calm the new fish and also not disturb the fish already present in the aquarium. The first step is to normalize the temperature of the water in the transport bag/container to the same temperature as the aquarium. In most cases this can be accomplished by simply floating the still sealed transport bag in the aquarium for 20-30 minutes to allow the temperature to stabilize. Once this is done, you can start to slowly adjust the water parameters to avoid sudden changes in the pH, hardness and even the nitrate levels. For marine fish it is also important to start to match the salinity of the water. With smaller fish, this adaption period can be accomplished by opening the transport bag, folding down part of the excess and letting the bag still float in the aquarium.

For larger fish or fish that might jump out of the bag it is better to gently pour the transport water into a small container or bucket. Slowly add a small volume of water from the aquarium to the container over a period of 30-60 minutes. If the fish is in a container, you can start a slow drip siphon (one drop every 5 seconds) from the aquarium into the container. You want to add enough water from the aquarium to match the amount of water in the transport container. If the fish shows no extreme signs of stress after this time, gently pour the container water into a bucket and catch the fish with a net to transfer to the new aquarium. Ideally you do not want to put any of the container water into the display aquarium to avoid possible contamination. 

If your fish shows obvious signs of extreme stress during the acclimation it is best to go ahead and net it out of the container and add it to the display aquarium, but be sure to turn off all the lights.

If you have any questions about fish acclimation, feel free to contact Gerber's Tropical Fish in Dayton, OH. You can visit them online to learn about their services, or give them a call at (937) 297-0515 if you have any questions.