Place fish filet on a sheet pan lined with parchment paper. Season with coriander, togarashi, salt and brown sugar.
Refrigerateat least 45 minutes to 1 hour. The longer it sits, the more flavor it develops.
While fish is marinating, preheat smoker using your favorite wood. Apple, oak and peach are great for smoking fish. Smoker should reach a temperature of 250ºF to 275ºF. Add more wood as needed to maintain temperature.
Place fish in smoker and cook until fish just starts to flake and reaches an internal temperature of at least 145ºF.
Allow to rest, flake fish and serve over rice or on tacos. Season to taste as needed.