The bag-floating method is half the job. Drip acclimation does the other half, and it takes one length of airline.
Fish cope with change, but not sudden change. The water in the shipping bag differs from yours in temperature, pH and hardness.
Step one: temperature
Switch off the tank light. Float the sealed bag for fifteen minutes.
Step two: drip
Pour fish and bag water into a clean bucket. Start a siphon from the tank with airline tubing, tie a loose knot to slow it to two or three drips a second, and let the volume double. Discard half and repeat.
Step three: transfer
Net the fish into the tank. Do not add bag water. Leave the light off until the next morning and do not feed until then.
Shrimp and marine invertebrates need longer: allow ninety minutes.
