Usually around four weeks. However, if a problem should arise from the new fish, say one of them gets sick, then I start all over with the coutdown. Once they are well and show no signs of problems, then I start the countdown of four weeks.
Normally the minimum for tank raised fish is 15 consecutive days with no problems or deaths. For wild caughts the minimum is 30 consecutive days. Longer never hurts anything.
wild fish...isnt that ilegal? and if not what kinds of wild fish do you catch? do you mean like the local flathead you catch at the beach or some angel in a rock pool? or even something fresh water.