Hot & sour fish soup

Name: Hot & sour fish soup
Prep time: 15 min
Cook time: 30 min
Total time: 45 min
Cuisine: Asian, Thai
Ingredients: 1 tsp coriander seeds; small piece ginger or galangal, sliced; 850ml chicken or fish stock; 175g thin rice noodles; 2 tbsp fish sauce; 2 fat red chillies , deseeded and thinly sliced; 3 garlic cloves , thinly sliced; 300g raw, tail-on tiger prawns; 200g/7oz skinless salmon fillet , cut into small cubes; 4 spring onions , chopped; handful coriander leaves; handful mint leaves , torn; juice 2 limes