Becoming angry and engaging in a quarrel does not invalidate the fast. However, such behavior diminishes the spiritual merit and virtue of the fast.
One of the essential etiquettes (ādāb) of fasting is that, together with the stomach, all limbs and faculties should also be made to observe a form of fasting. Besides the stomach, a human being possesses many organs, faculties, and senses such as the eye, the ear, the heart, the imagination, and the intellect. While fasting, a person should restrain all these faculties from idle pursuits and from what is unlawful, directing each of them toward its particular duty of worship and servitude.
For example, one should restrain the tongue from lying, backbiting, coarse, and offensive speech, and instead occupy it with matters such as the recitation of the Qur’an, remembrance of God (dhikr), glorification (tasbīḥ), sending blessings upon the Prophet (ṣalawāt), and seeking forgiveness (istighfār).