A sk the dealer to hold each fish in the net against the tank front while you give it a final inspection. T he dealer will pack your fish in polythene bags, which should be placed in brown paper bags or a carrier so the fish won't be frightened by what is going on around them. Ideally take along a suitably sized lidded bucket for very large specimens. Resist the temptation to keep checking the fish in transit - you will be causing additional stress. Equalization normally takes only minutes, when the temperatures are within a degree or so of each of each other the fish can be released.
S ubmerge the top of the bag, ensure it is wide open, the gently tip the fish out.
Always check they are all free. N ote in your log book the details of your purchase.