Preheat the oven to 375°F.

Prepare a large baking sheet by lightly coating it with coconut oil.

Cut sweet potatoes into 1-inch cubes.

In a bowl, toss the sweet potatoes with 1 tablespoon of coconut oil and 1/2 teaspoon of salt.

Spread the sweet potatoes on the prepared baking sheet.

Roast the sweet potatoes for about 25 minutes, or until they just start to become tender.

While the sweet potatoes are roasting, prepare the paiche fillet.

In a small bowl, combine the lime zest, lime juice, chili powder, and remaining 1/2 teaspoon of salt.

Sprinkle the paiche fillet with the lime juice mixture, ensuring it's evenly coated.

Push the partially roasted sweet potatoes to one side of the baking sheet.

Brush the other side of the baking sheet generously with more coconut oil.

Place the paiche fillet on the oiled portion of the baking sheet.

Continue to roast the paiche and sweet potatoes for an additional 15 to 20 minutes.

Roast until the fish is opaque in the center and the potatoes are very tender.

Remove the baking sheet from the oven.

Sprinkle the roasted fish and sweet potatoes with fresh cilantro and fresh mint.

Serve immediately.