Peel the potatoes, cut them into smaller pieces and cook in salted water until soft.
Chop the vegetables into same-sized pieces. Roughly chop the onions.
Carefully pat the fish dry with kitchen towel or similar (wet skin loves to stick to the pan). Take your time to heat two frying pans and add oil to both.
With the first pan on a medium heat, begin to fry the fish skin side down. Cook until golden brown, then turn and give it time to cook through.
In the other pan, make a start on the veg. First add the courgettes / zucchini to the heated pan. After a minute, add the peppers, after two, the onions. Fry for a further minute or two, then take off the heat and stir in the herbs and spices and the garlic. The vegetables should remain a little crunchy - there is no need to fry the life out of them :)
Beat the potatoes with a whisk until smooth adding milk as required. Season to taste.
Place the fish on the mash and add the vegetables around it. You could also add a drizzle of chimichurri sauce.