First, we will create a marinade by combining ginger paste, tomato paste, Greek yogurt and curry powder in a small bowl. Chop the basa fillets in bite sized pieces, and place them in a bowl. Add the marinade to the fish, and stir to coat evenly.
Place the fish in the refrigerator, and leave it to marinade for at least 30 minutes, or up to several hours. I like to do this step in the morning, and leave the fish in the refrigerator until I’m ready to finish dinner in the afternoon. This allows the fish to absorb the curry flavor.
Heat up the oil in a pot on medium heat, and add finely diced onion. Sauté the onion for a few minutes until it’s soft and translucent. Add finely minced garlic and chili, and sauté for another minute.
Then, add the curry powder, tomato paste, and the fish to the pot along with all the marinade.
Cook the fish curry while stirring occasionally for about 5 minutes, or until the fish has cooked through. You’ll know that the fish is ready when it starts to flake at the touch of a fork. Avoid overcooking it, or the fish will flake and practically dissolve into the sauce.
Serve fish curry immediately while it’s still hot with your favorite side dishes!