In a bowl, add the bread and add enough water to cover it. Set it aside to soak.
In a separate bowl, add the fish roe, olive oil and lemon juice. Mix until incorporated.
Squeeze the bread with your hands to remove as much water as possible. Add it to the bowl with the fish roe and add the onion, parsley, dill and mint. Season to taste.
Mix thoroughly with your hands. Cover the bowl with cellophane wrap and refrigerate for 1 hour.
Place a large pot, full of a generous amount of sunflower oil, over high heat and let it get hot. Pick up about 30 g ( 2 tablespoons) of the fish roe mixture and shape into round balls.
When the oil is hot, add the fish roe balls. Fry until golden and crunchy.
Transfer to a plate lined with paper towels, to drain.
Serve the fish roe fritters warm, along with parsley and thinly sliced onions.