Bring the dashi to a simmer in a 4-quart saucepan over medium heat. Add the lemongrass, galangal, cilantro, habanero, fish sauce and lime juice and bring the liquid to a simmer. Add the catfish and the coconut milk and cook until the fish is just cooked through, about 4 to 5 minutes. Remove from the heat, ladle into soup bowls and serve immediately.
Recipe courtesy of Alton Brown, 2010