Check out this video:
http://www.youtube.com/watch?v=4h6CsbejiXI
Here Dr Loh is introducing silver perch to a circular tank.
The unopened bag was first floated on the surface for 5-10 minutes to equalise any temperature differences so as not to cause temperature shock. It is important to leave the bag unopened at this stage (see explanation at this link –
https://thefishvet.wordpress.com/2012/02/06/bagged-fish-water-quality-changes/).
Then the bag is opened and new tank water is added to the fish bag to double its volume. This will dilute any wastes that had built up in the bagged water and will allow fish to acclimatise to the new water conditions. An air stone may be added to aerate the water if there is a high stocking density in the bag.
After another 5-10 minutes, fish can be released into the new tank.
