Place onions, garlic, lemons, oranges, celery, and jalapeno peppers into a 4 or 5 gallon pot. Season with pepper and seasoned salt; fill with enough water to fill the pot 3/4 full. Bring to a hard boil over intense heat, and allow to boil for 20 minutes.
Add the crawfish, cover, and boil for 20 minutes until the shells turn red. Drain and eat.