Musannaf Ibn Abi Shayba 16:355

Abu Bakr narrated to us, he said: Waki’ narrated to us, from Mujashi’ Abu al-Rabi’, from Kuhayl, from his father, who said: Ali used to pass by us while the eel (al-jiry) was on our dining mat, and we were eating it, and he did not see any harm in it.