During whose period the fish (haram) and liver was forbidden to eat

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We did not find any religious text stating the ruling on consuming fish and liver in the previous divine laws. However, it is enough for us to know that those things are Halaal (lawful to eat) in the Islamic Sharee'ah. It was reported on the authority of Ibn ‘Umar that the Prophet said: “Two kinds of dead meat and two kinds of blood have been made lawful for us. The two kinds of dead meat are fish and locusts, and the two kinds of blood are the liver and spleen.”

Allaah Knows best.