Sahih Muslim Book 21, Hadith Number 4761.

Chapter : It is permissible to eat the animals of water even if they are dead.

Jabir b. ‘Abdullah reported that Allah’s Messenger (may peace be upon him) sent an expedition to the sea coast and I was one among them. The rest of the hadith is the same with a slight variation of wording that in the hadith transmitted on the authority of Wahb b. Kaisan (the words are): “The army ate out of that (the whale) for eighteen days.”