Source: Tafsir al-Ahlam al-Kabir (Ibn Sirin)
The crab in a dream is a man of bad character, difficult to deal with. Whoever befriends one befriends a man with these traits. Eating it is unlawful money.
Source: Ta'tir al-Anam fi Ta'bir al-Manam (Al-Nabulsi)
The crab indicates a gossiping man who strives for corruption. Its bite indicates harm from an enemy.
Source: Al-Isharat fi Ilm al-Ibarat (Ibn Shahin)
The crab is interpreted as a hateful man. Whoever sees himself eating it will gain wealth from a bad man.