Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.
Dice the bell pepper and zucchini into uniform bite-sized pieces.
Toss the vegetables on the baking sheet with half of the olive oil and a pinch of the salt and pepper.
Roast the vegetables for 15-18 minutes until they are tender and show slight caramelized edges.
Pat the tilapia and shrimp dry with a paper towel, then season both sides with garlic powder, smoked paprika, and the remaining salt and pepper.
Heat the remaining olive oil in a large non-stick skillet over medium-high heat.
Place the tilapia in the skillet and sear for 3-4 minutes per side until golden and the fish flakes easily with a fork.
Add the shrimp to the skillet during the last 3-4 minutes of cooking, searing for about 2 minutes per side until pink and opaque.
Remove from heat, drizzle the fresh lemon juice over the seafood, and serve immediately alongside the roasted vegetables.