Put the fish in a large, oval fish pan. Add cold water until it covers the fish, around 1.3 gallons. Stick a meat thermometer into the thickest part of the fish. Add salt and bay leaves. Bring it to a boil. When the water is just barely boiling, turn off the heat. Let the fish steam in the pan until the thermometer shows a core temperature of between 150 and 163°F.