hey mate remember to not take undersize fish.
also u can by bream in pet shops for like 20 bucks, yellowfin.
i have never done it before but i am also interested, i heard that u set the tank up with salt water from the sea and gradually add fresh water in once every 2 days.- just take a little salt out then add fresh, there are heaps of methods of doing it. im sure u will get more infomation.
cam