1In a large pot, melt the butter over medium heat.
Add the diced onions, carrots, and celery. Cook until the vegetables are tender, about 5-7 minutes.
Add the diced potatoes and fish stock to the pot. Bring to a boil, then reduce the heat and simmer until the potatoes are tender, about 10-15 minutes.
Stir in the mixed seafood and cook until the seafood is opaque and cooked through, about 5 minutes.
Add the milk, salt, black pepper, and thyme. Stir to combine and heat through, but do not boil.
Taste and adjust seasoning if necessary.
Serve hot and enjoy your Classic Seafood Chowder.