Slice the green onion diagonally.

Place the carp fillets and water in a pot, and bring to a boil over high heat. Once boiling, reduce the heat and skim off any foam.

When the fillets are cooked, add the green onion and miso.

Once it comes to a boil again, slice the tofu and add it to the pot. When it boils, it's done.

You can sprinkle shichimi togarashi or ground sansho pepper to taste.