Sprinkle Mahi Mahi with lemon juice, season with salt and pepper and cook according to package directions. Sauté onions until translucent in butter in a heavy, deep skillet. Add mushroom sand tomatoes; simmer for 5-7 minutes. Add fish juice from the pan; bring to a boil. Pour sauce over Mahi Mahi. Sprinkle with chives or parsley and serve with rice.
Source: Icelandic USA Inc.