What is the story of Prophet Musa's whale mentioned in Surat Al-Kahf, and is it like the well-known whale or different? And what is the interpretation of Allah's saying: "But when they reached the junction between them, they forgot their fish, and it took its course into the sea, a pathway," and was the fish accompanying Prophet Musa?

The whale of Moses was a natural fish he was commanded to carry, and its loss was a sign of Al-Khidr's location. Moses and his servant Joshua, peace be upon them both, forgot it. Then the fish made its way through the sea as if carving a tunnel through the earth. It was said that the fish was dead and salted, then it came back to life by Allah's permission. It is mentioned in the Hadith that Moses, peace be upon him, was commanded to carry the fish in a basket, and wherever he lost it, that would be the location of Al-Khidr.