Thaw fish if frozen, Preheat oven to 350 degrees F.
In a medium bowl stir together the potatoes and yogurt. Salt and pepper to taste.
In a skillet heat the olive oil over medium-low heat. Add basil, garlic and the sundried tomatoes. Heat until the garlic just starts to color.
If you are using the edamame add to pan and cook 3 to 5 minutes. If using peas or snap peas add to pan, stir to coat and remove from the burner.
Split the potatoes between two individual casserole dishes and put in half of the dish. Remove the pea (edamame) mixture with a slotted spoon and put half in the other side of the casserole dish from the potatoes. Put half of the tomatoes on top of the pea mixture in each dish. Place a fish fillet on top of each pea mixture. Brush the top of the potatoes and fish with the basil oil left in the skillet. Salt and pepper the fish to taste.