Take your fish home as soon as possible; the bag has a limited supply of oxygen. Keep bags warm for tropical fish. It is a good idea to leave the fish in the paper bag where it is darker and will not be stressed by bright light. In addition the bag will help to insulate the water to a certain extent. Nonetheless, get your new pets home as soon as possible.

Once home, make sure your aquarium water is the proper pH and temperature for your new fish. Float the unopened bag in the aquarium for 15 minutes. This allows the temperature of the water in the bag to reach an equilibrium with the tank water slowly-- reducing the risk of thermal shock. The fish can then be safely released into their new home.

For especially sensitive species it may be prudent to take an additional step. After allowing the 15 minute float, open the bag and pour a volume of tank water equal to half the volume already in the bag into the bag with your new fish. Float this bag upright in your aquarium for 10 minutes and then release. This step simply allows for a slower acclimatization period and happier fish!