Add the onion, garlic, bell pepper, and celery and cook for 5-7 minutes, or until the vegetables are softened.
Stir in the flour and cook for 1-2 minutes, or until the flour is well combined.
Add the chicken broth, milk, heavy cream, bay leaf, thyme, paprika, and white pepper to the pot and bring to a boil.
Reduce the heat to low and simmer for 15-20 minutes, or until the vegetables are tender.
Add the halibut to the pot and simmer for 5-7 minutes, or until the fish is cooked through.
Discard the bay leaf and season the chowder with salt to taste.
Serve the halibut chowder hot, sprinkled with chopped parsley.
Note: You can also add other ingredients to the chowder, such as diced potatoes, frozen corn, or sliced carrots, for extra flavor and nutrition. Just add them to the pot with the vegetables and cook for a few minutes before adding the halibut. You can also use other types of fish, such as cod or haddock, in place of the halibut if desired.