Maliks Muwatta Book 25, Hadith Number 10.

Yahya related to me from Malik from Zayd ibn Aslam that Sad al-Jari, the mawla of Umar ibn al-Khattab asked Abdullah ibn Umar about fish which had killed each other or which had died from severe cold. He said, “There is no harm in eating them.” Sad said,’ ‘I then asked Abdullah ibn Amr ibn al As and he said the same.”