In a large bowl, cover the rice vermicelli with hot water. Let stand until softened, about 10 minutes, then drain.
Heat the oil in a medium saucepan. Add the garlic, ginger, Sriracha sauce and red bell pepper and cook over moderately high heat, stirring, until fragrant, about 2 minutes. Add the water, tomato juice and pineapple and boil over moderately high heat for 10 minutes. Stir in the fish sauce and lime juice.
Bring a large skillet of water to a simmer. Season the sea bass with salt and pepper, add to the skillet and poach over moderate heat until just cooked through, about 5 minutes. Using a spatula, transfer the fillets to a large plate.
Bring the water back to a boil over high heat. Add the rice vermicelli and boil until al dente, about 1 minute. Drain the vermicelli and transfer to shallow bowls. Top with the sea bass fillets and ladle the tomato-pineapple broth all around. Top with the scallions, cilantro, mint, peanuts and shredded carrot and serve right away, with lime wedges.