Chop the onion and bacon.

In a large saucepan, cook the chopped onion and bacon over medium heat until the onion is tender, then drain any excess grease.

Add the evaporated milk, whole kernel corn (undrained), chopped clams (undrained), cubed potatoes, butter, salt, and pepper to the saucepan.

Cover the saucepan and cook over medium heat, stirring occasionally, until the potatoes are tender, approximately 20 minutes.

Gently stir in the cooked fish fillets (haddock, cod, or flounder) that have been broken into pieces.

Heat the chowder through until the fish is warmed.

Ladle the chowder into bowls.

If desired, top each bowl with crumbled cooked bacon and minced chives before serving.