Keeping Fish Flesh Firm In A Curry

For a curry you will need to use a firm fish like halibut or king fish so that it doesn’t disintegrate. Another thing I do is to fry the fish on both sides till it’s about 3/4th done, and then add it to the curry.

I don't add in any "extra" ingredient to keep fish in a curry firm. You do that best by choosing a firm flesh type fish to start with, not allowing the mixture to do more than a simmer, and not overcooking the fish. If your curry recipe calls for a long cooking period, it may be best not to add the fish in until the last 15 minutes or so, depending on the thickness of your fish. Some recipes I've seen also call for salting the fish and letting it sit for 10-15 minutes before cooking. You'd need to reduce the other added salt in the dish, but salting fish would firm it up by removing excess water from the flesh. It would absorb the cooking sauce to replace the lost liquid, so you'd still want to watch over all cooking temperature and timing. Aside from all this, leaving the fish more or less on the bones can also help keep it together, if that is an option and you don't mind picking out bones.