Prepare the products. Gumbo can be prepared with any sea fish – walleye, cod, dorado, flounder, sea bass. The main thing is that there are no small bones in the fish. I have a cod fillet. Rinse the rice in several waters, put it in a saucepan with cold water and leave for 30 minutes. Drain the water. Pour a large amount of fresh water into a saucepan, bring to a boil over high heat and cook for 7 minutes. Reduce the heat and cook for another 10 minutes. Put the rice in a colander and let it dry.