Wash herbs, pat dry, chop finely. Peel garlic and press it through a garlic press. Mix herbs, garlic and olive oil. Wash lemon, halve lengthwise, cut into slices. Wash the barbels and remove the scales. Cut several times on one side.
Season fish inside and out with salt and pepper. Fill herb mixture and lemon slices into the incisions and abdominal cavities. Place on banana leaves, in aluminium bowls or in grilled fish cutlery. Cook on the hot grill while turning for about 20 minutes. Serve with grilled tomatoes or peppers