How can I take out the bones of a fish on Shabbat?
One should ensure that the flesh of the fish is pulled off from the bones, rather than taking the bones out of the fish.
This is not always possible, and another method is to take bones out together with some flesh, with the intention of eating the flesh on the bones.
A third option is to place the fish with the bones in one’s mouth, and take out the bones from one’s mouth.
These are the three best options. However, the Mishnah Berurah also justifies the practice of removing bones before eating the fish. If this is done, the bones should be removed right before eating.
Based on the Ramban and the Ran, the Bi’ur Halacha (319:4) supports the position of Mahari Abulafia, who writes that it is permitted to remove bones from fish right before eating.
However, the Chazon Ish (54:1) disputes this understanding, understanding that one must place the food in one’s mouth, and only then is it permitted to remove the bones.
The Shemiras Shabbos Kehilchasa (3:11-13) brings the two opinions, and he writes that essentially one should be stringent, yet adds that there is support for those who are lenient if they remove the bones as they are eating (immediately prior to eating) and not before that point.
The Shevet Ha-Levi (Vol. I, no. 83) likewise supports the Mishnah Berurah’s argument, and the Ben Ish Chai (Year 2, Beshalach 10) also permits removing the bones and eating the meat/flesh right away, explaining that since this is how everyone eats it, it is not considered “derech bereira” (separation) but “derech achilah”.