Asian hot and sour fish soup

Name: Asian hot and sour fish soup
Cook time: 20 min
Total time: 20 min
Cuisine: Asian
Ingredients: ginger grated to make 2 tbsp; red chilli ½, finely chopped; spring onions 2, thinly sliced; lemongrass 1 stalk, lightly bashed; light chicken stock 700ml; soy sauce 3 tbsp; rice vinegar 2 tbsp; skinless firm white fish 400g, cut into chunks; baby spinach 2 handfuls, chopped; Thai fish sauce 2 tsp; cooked rice or rice noodles to serve (optional)