I usually use some of the Grouper fishes we have around here, but I also like using Nile perch.
About the cooking method, I tend to like using pots a bit more for this dish.
Here's a recipe (for a 30 centimeters diameter pot).
Ingredients:
1 Bell Pepper
1 Tomato
Handful (I mean a REAL handful) of Cilantro
3 Whole Garlics
Half a cup of Canola oil
Chicken soup powder
3 FULL tea spoons of sweet Paprika
2 tea spoons of spicy Paprika
Pinch of Turmeric powder
Pinch of Cuminum powder
Pinch of white pepper powder
Lots of "Kashmiri" peppers (or whatever you call them)
And of course the fish!
Instructions:
Soak the fish in lemon juice (and of course wash it when you're done).
"Pad" the pot with the sliced tomato and bell pepper (don't stack them).
Now put a layer of "Kashmiri" peppers on top of it (De-seeded if you just want to the flavor).
Spread about 5/6 of the cilantro over everything in the pot, and do the same with the garlic.
Place the fish on top of everything, and then spread what's left from the cilantro and garlic.
Now take a bowl and put that half cup of oil in it.
Put inside ALL of the paprika (sweet and spicy), chicken soup powder, turmeric, cuminum, white pepper and mix it all together.
Pour it all over the pot, fill the bowl with half a cup of water and pour it also.
*To this point, the recipe is mildly hot and nothing more!*
Now you can add you favorite chile powder/peppers for some real heat.
Boil it on a medium fire with a little hatch.
After boiled, lower your flame for the rest of the cooking.
IMPORTANT: Every once in a while open the top of the pot, get some of the sauce on a spoon and pour it on top of the fish (It's a must do!).
It should be ready in 30 to 40 minutes, but the real indication is the garlic, it should be all soft and nice.
Enjoy.