Tuna Belly in Olive OilPremium Spanish Tuna Belly in Olive Oil by Zallo Tuna Belly in Olive Oil by Zallo is the ultimate luxury in tinned fish. Known as "ventresca" in Spanish, tuna belly is the most prized cut of the tunaincredibly tender, rich, and buttery with a melt in your mouth texture that's unlike any other part of the fish. What is Tuna Belly (Ventresca)? Tuna belly comes from the underside of the tuna, where the fish stores its fat reserves. This makes it: The