Meanwhile while the fish marinates, In a wok or karahi, on medium heat, add oil, and let it heat up.
Now add Serrano pepper, and whole spices.
Add onion and sauté until translucent.
Now add ginger garlic paste give it a mix.
Add tomatoes and keep mixing it for 5 minutes.
Now add powdered spices and salt.
Add tomato paste, chicken cube, and water and give it a good mix.
Now add the marinated fish mixture.
Turn the fish with in the curry carefully now cuz if handled roughly the fish would break.
After mixing let the cook the fish for 2-3 minutes on each side.
Turn the stove to medium-low.
Cover the lid and let it cook for 3-4 minutes.
Remove the lid.
Squeeze some fresh lemon juice.
Sprinkle some cilantro.
Turn off the stove.
Serve it hot immediately and serve with a Chapati or Naan.
Enjoy!