As bang guy mentioned, keep the fish warm. I didn't go into all the details of the drip-acclimation process, so I'll add it now. I always temp acclimate the bag(s) of fish for 15-20 minutes by floating the bags(s) in the tank before starting the drip-acclimation. I prefer to use an airline valve to control the flow, which should be about 4 drops per second. Always use a sterile plastic or glass container to acclimate the new additions... never use styrofoam. Start by opening the bag(s) and pouring the contents into the container. Start the slow-drip, and let it go until the water volume doubles. Pour half the water out and discard it. DO NOT PUT IT IN YOUR TANK! Allow it to double again, and repeat. If you drip correctly, you will pour water out of the container at least 4 times. After removing water a minimum of four times, the shipping water should have been completely replaced. While tempted to pour the fish into the tank, do not do it. Either net the fish, or as I do, gently scoop them into your hand and allow the water to drain between your fingers. Gently place your hand in the tank, slowly open your hand, and allow the fish to swim out at it's leisure. I find this method to be the least stressful, and fish will normally not dart for a hiding place. Always do this in a dimly lit room and tank, as it cuts down on curiosity and possible aggression from current fish. It also allows the new arrival(s) a chance to get accustomed to their new surroundings without being intimidated.
