In a 1-gallon resealable freezer bag, combine the garlic, lemon grass, habaneros, shallots, fish sauce, ginger, sugar and turmeric. Mix all the ingredients around in the bag, then add the fish and seal the bag. Shake to coat the fish in the marinade. Marinate in the refrigerator for 4 to 6 hours.
Cook the rice noodles according to package directions. Quickly rinse in cool water, drain well and divide among 4 serving bowls.
Heat the vegetable oil in a large saute pan over medium-high heat. When hot, add the fish along with its marinade. Remove the lemon grass and discard. Sprinkle the fish with the salt and cook, undisturbed, for 4 minutes. Flip the fish pieces over to lightly brown the other side, and cook another minute or so. Toss gently with a rubber spatula until all of the fish is cooked and the shallots are beginning to brown. Scatter the scallions, basil, cilantro and mint over the top. Spoon the fish over the rice noodles. Serve.