CRAWFISH MAC AND CHEESE

1 (16-oz.) package elbow macaroni 2 T. butter 1 lb. fresh crawfish tails 1 (8-oz.) jar pimientos, drained 2 c. shredded mozzarella cheese 2 c. shredded sharp cheddar cheese 1 c. shredded Parmesan cheese 1 c. shredded Gruyere cheese 1…