Fish soup (Kakavia)

4 tablespoons Sitia Extra Virgin Olive Oil
3 lbs whole fish (bass, cod, red snapper, pike, grouper)
2 onions, sliced into thin rings
5 - 6 medium potatoes, peeled and cut into quarters
juice of 2 lemons
salt and pepper

Scrape and wash the fish and remove guts. Cut into large slices. In a soup pot, heat olive oil and soften onions until lightly brown. Add potatoes and cover with enough water. Boil for 10 minutes, then add fish, salt and pepper and continue cooking for a further 25 - 30 minutes. Remove pot from heat and pour in lemon juice.