hardy fish, float for about a half an hour then net into tank as stated above.
sensitive fish, I empty them into a bucket first.....I have never been good at the airline tubing thing, so I use a 3ml syringe and squirt a syringe or two every 10 minutes or so for about an hour.....making sure the water temperature is kept within normal range of course......then I scoop about half the water out of the bucket and empty into the sink, then continue to squirt water into the bucket from the tank for the next hour. Then I scoop out another half the water in the bucket. By the time the third hour comes around, the water in the bucket should be mostly water from the tank. Then I net the fish out and place in the tank. Also, if your running pressurized co2 like I am, I make sure the ph isn't a lot different, if it is quite a bit different from the water in the bucket, I turn off the co2 in the tank and aerate the tank for a bit to offgas the co2 until the ph comes into a better range closer to the water in the bucket. I have had fish in the past get a bit of a ph shock since the ph in my tank is pretty low while the co2 is pumping.