Allow cooked vegetables to cool and mix with mushrooms and basil. Set aside. Place tomatoes, garlic and basil in a blender and puree. Place in saucepan and bring to a simmer, add olive oil and season with salt and pepper. Do not boil. Keep warm. Toss fillets in olive oil and place in frying pan. Saute for 2 minutes per side. Season with salt, pepper and lemon juice. Warm the vegetable mixture in frying pan. Place fish on plate, top with vegetable mixture and ladle sauce on top.