In a large heavy stockpot add oil and bring to a heat add garlic, ginger and lemon grass and light saute for a minute. Add in the clam juice and chicken broth and bring to a boil. Reduce the heat to a simmer and after 5 minutes remove the garlic, ginger and lemon grass. Turn the heat back up add in the rock fish, shrimps, mussels and Napa cabbage and when the stock come back to a boil turn off the heat. Add in the oyster sauce, wine, salt and pepper to taste. Serve in a large soup bowl and add drop of sesame oil and top with green onion and parsley leaves.