Marithes: Whole Fried Picarel or Whitebait Smelt. In Greek: μαρίδες, pronounced mah-REE-thess. The smaller the better as far as I'm concerned! If the fish are less than 2 inches long, they don't need to be gutted; from 2-3 inches long, they do, and anything over that is too big if it's a picarel! Whitebait smelt (the smallest smelt) is an acceptable substitute, up to 5-6 inches long, maximum.