The Great Sea Serpent

One sunny day, when a little sea fish was swimming joyfully with his eighteen thousand brothers and sisters, the water was darkened by an enormous eel who came from above and was heading deeper into the sea. It disappeared very quickly and as soon as the calm had returned, the cutest little fish, who was also the most curious, went looking for information to find out who this newcomer to the Ocean was. Could it be the great sea serpent?