It was narrated that Abu Dharr said:
"I heard the Messenger of Allah say: 'Everyone in the universe, in the heavens and on earth, prays for forgiveness for the scholar, even the fish in the sea." (ID)
English reference (ID): Vol. 1, Book 1, Hadith 239 (ID)
Arabic reference (ID): Book 1, Hadith 245 (ID)