Melt butter in a large pot over medium heat.
Add chopped onion and minced garlic, sauté until translucent.
Stir in diced potatoes and cook for 5 minutes.
Pour in seafood stock and bring to a boil.
Reduce heat and simmer until potatoes are tender, about 10 minutes.
Add heavy cream and stir well.
Incorporate shrimp, clams, and diced fish.
Season with salt, pepper, and fresh dill.
Cook for an additional 5-7 minutes until seafood is cooked through.
Serve hot, garnished with fresh parsley.