Corn and Crawfish Chowder Soup

Name: Corn and Crawfish Chowder Soup
Ingredients: 1 stick - 8 tbsp - butter or margarine; 2 tbsp flour; 1 onion, chopped; 1 to 2 lbs peeled crawfish tails; 1 quart milk or cream; 2 cans cream corn; 1 (15 oz) can whole kernel corn; 1 (10 oz) can cream of potato soup; 1 small bell pepper, chopped fine; 1 stalk celery, chopped fine; 2 cloves of garlic, chopped fine; 1/2 cup chopped parsley; 1/2 cup green onion; 2 tsp Cajun seasoning; Pepper to taste; 4 medium red potatoes parboiled (optional)