Hot and sour fish soup

Ingredients

• 1 tsp coriander seeds
• small piece ginger or gangland, sliced
• 850 ml chicken or fish stock
• 175 g thin rice noodles
• 2 tbsp fish sauce
• 2 fat red chilies , deseeded and thinly sliced
• 3 garlic cloves , thinly sliced
• 300 g raw, tail-on tiger prawns
• 200 g/7 oz skinless salmon fillet, cut into small cubes…