Cut potatoes in 1/2 inch chunks, and the other veggies in slightly larger chunks. Toss all with 2 or 3 tsps of olive oil, and about 1 tablespoon of vinegar. Season to taste. Roast at 425 for about 45 minutes, or at 450 for 1/2 hour, and the rest of the way with the fish. Stir about every 15 minutes or so, to get the juices mixed and rotate the veggies. I roasted these in a small (brownie sized) baking dish.