Add water to the Instant Pot and insert steamer basket.
Add zucchini to basket in an even layer. Add orange roughy fillets on top. Squeeze lemon juice over fish. Season with salt and pepper. Distribute butter pats on fish and zucchini. Lock lid.
Press the Manual or Pressure Cook button and adjust time to 3 minutes. When timer beeps, quick-release pressure until float valve drops. Unlock lid.
Transfer fish and zucchini to two plates. Garnish with parsley. Serve warm.
Notes
PER SERVING: CALORIES: 363 FAT: 22g PROTEIN: 30g SODIUM: 1,302mg FIBER: 2g CARBOHYDRATES: 6g NET CARBS: 4g SUGAR: 4g