Lemongrass Thai fish soup

1⁄4 cup chopped lemon grass 
4  coins of ginger
3  cups fish stock or 3 cups vegetable stock 
2 (14 ounce) cans coconut milk 

1 Tablespoon paprika
3 -6 small red chilies, cut into rounds 
3  scallions, minced 
2  tablespoons fresh cilantro, chopped 
3⁄4 lb white fish fillet, cut into bite-sized chunks
2  juice from 2 lime

3  tablespoons fish sauce 

Simmer  lemongrass in 1 cup of the stock for 1/2 hour. Add more liquid as necessary (you want to end up with 1 cup of stock).

In a large saucepan, simmer the coconut milk and 2 remaining cups of stock, uncovered, for 5 minutes.

Add the chiles, scallions, cilantro, and fish.

Strain the lemongrass mixture and add that liquid to the pot (you can toss out the herbs).

Simmer, uncovered, until the fish is just cooked. Remove from heat.

Stir in the lime juice and the fish sauce, adding more if desired. Add basil, chopped scallions, a fresh sprigs of cilantro