Add vermicelli to pan of boiling water, boil uncovered 2 minutes or until just tender, rinse and drain. Remove and discard heads from fish, fillet fish, reserving bones. Remove and discard fish skin. Cut fillets into strips. Combine water, powder, lemon grass, mint, basil, lime leaves, and dried and fresh chillies in pan, simmer covered for 30 minutes. Add fish bones, simmer for another 10 minutes. Strain resulting stock, discarding bones and chilli mixture. You need 1125 ml of stock so add water if necessary. Place extra lime leaves in a bowl, cover with warm water, stand 20 minutes. Drain, and slice leaves thinly. Return stock to pan, add chilli paste, fish strips, coconut cream, sliced lime leaves, sprouts, salt and sugar and bring to the boil. Divide vermicelli into serving bowls, pour soup over it. Garnish with extra sliced chillies, baby basil leaves and bean sprouts. Chilli paste. Blend or process all ingredients until smooth.