Sunan Ibn Majah, Book 1, Hadith 245 (In-Book) ⓘ
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."
حَدَّثَنَا هِشَامُ بْنُ عَمَّارٍ، حَدَّثَنَا حَفْصُ بْنُ عُمَرَ، عَنْ عُثْمَانَ بْنِ عَطَاءٍ، عَنْ أَبِيهِ، عَنْ أَبِي الدَّرْدَاءِ، قَالَ سَمِعْتُ رَسُولَ اللَّهِ ـ صلى الله عليه وسلم ـ يَقُولُ " إِنَّهُ لَيَسْتَغْفِرُ لِلْعَالِمِ مَنْ فِي السَّمَوَاتِ وَمَنْ فِي الأَرْضِ حَتَّى الْحِيتَانِ فِي الْبَحْرِ " .
also referenced under: Hadith 239 (Reference) & Volume 1, Book 1, Hadith 239 (DarusSalam)