In a medium bowl, combine carom seeds, red chili powder, turmeric, and kosher salt. Gently coat the firm-fleshed white fish pieces with this aromatic marinade, adding the fresh lemon juice. Allow to marinate for at least 15 minutes.

Heat 2 tablespoons of avocado oil in a large, deep pan over medium heat. Sauté the finely chopped yellow onions for about 18 minutes until golden brown.

Deglaze the pan with a splash of water, then add the finely chopped garlic and ginger. Stir for an additional 2-3 minutes until fragrant.

Sprinkle in coriander powder, cumin powder, and Kashmiri chili powder. Stir well to bloom the spices for about 2 minutes.

Add the finely chopped tomatoes to the spiced mixture and stir, cooking until they soften and the oil separates, about 5 minutes.

Pour in 1 cup of water, stir to combine, and bring to a gentle simmer. Cover the pan and lower the heat, allowing flavors to develop for about 10 minutes.

In a nonstick skillet, heat the remaining avocado oil over medium-high heat. Place the marinated fish pieces and cook for about 4 minutes on each side until golden and cooked through.

Uncover the curry and check its consistency, adding water if you prefer a thinner sauce. Slide the cooked fish into the curry and simmer for an additional 2-3 minutes.

Serve hot, garnished with green chili peppers, black pepper, julienned ginger, and cilantro leaves alongside naan or rice.