Eel. Really only found in Western Greece and increasingly endangered elsewhere.
If you like them, the island with no name in the Lake of Ioánnina prepares eels, along with frogs from the lake, on hot roof tiles. Χέλι καπνιστό (chéli kapnistó) (smoked eel) is a speciality of Árta.
Image by Kils, Creative Commons License