Crush Cinnamon stick, Star anise, Cardamom. Place this in a cheese cloth and tie well. Note: if are ok with these in soup you don't need to tie in a cloth. tying in cloth will help easily remove this from soup.
In a pan heat oil. add shallot (sambar onion), ginger, garlic and sauté until onion turn translucent.
Now add water as needed, tied spice cloth bag, fishes and bring the soup to boil.
Now add black pepper, salt and cook until the fish is cooked. Remove the spicy cloth bag. Garnish with spring onion and serve.
Healthy soup so will not be thick. You can use meaty fish pieces too.