Bleeding is an action of removing blood from a fish. Why bleeding? By bleeding and subsequently removing the blood and gut before cooking or preserving a fish, the fish will be more presentable and taste better. That is why the fish in the seafood restaurant that was cooked immediately after killing it taste better than fish that we bought in the market that is sold without bleeding and gutting. There will be no blood pool in the muscle (blue black) which occur normally on wild caught fish that was left to die flip floping on boat deck or in the ice box.
How to bleed a fish. A straight forward method is to cut or slit the fish throat near the gill and let the fish die in a bit of ice water. Once the fish stop moving, gut and put the fish on ice. This is true for most marine fish. for fresh water fishes, the same applied except maybe for some cat fish like patin and large knife fish (belida). For patin, its take sometime to stop moving and even after guttin , blood still come out from the two holes in the stomach cavity. What I have done is to clean up the patin's cavity including the black thing near the bone in the stomach cavity which is actually its kidney. Then I will place a crumble up piece of tissue paper or newspaper in the stomach cavity to absorb the blood that is still coming out. Thus my believe that the only fish that taste better after freezing is patin. As for belida, it should be gutted and bleed by cutting the tail and hanging the fish to let the blood out from the cut in the tail. White belida of over two kilo will have white meat at best to make fish ball. the stomach area should be coo/steam separately. Fish below 2 kg will have pinkish meat and produce 2nd grade fish ball. The meat of the star belida (belida bintang) is a little bit fishy and consider a 2 nd grade fish ball. Some people will add on the lesser knife fish (selat) meat or haruan meat to increase the volume of the meat.