- "T'was a student who gave me Francis... One spring afternoon I discovered a bowl on my desk, just a few inches of clear water in it. Floating on the surface was a flower petal... as I watched, it sank... just before it reached the bottom, it was transformed, into a wee fish. It was beautiful magic, wondrous to behold. The flower petal had come from a lily... your mother. The day I came downstairs, the day the bowl was empty, was the day your mother..."
- —Horace Slughorn regarding his pet fish Francis[src]
The fish came into Slughorn's possession when Lily set the petal to float inside a bowl filled with water. When Slughorn found his gift, the petal sank down in the bowl and turned into Francis, much to the Professor's delight. Slughorn kept Francis for many years, until the morning of 1 November, 1981, when he found Francis had disappeared. This was due to Lily's death at the hands of Lord Voldemort.
- Harry Potter and the Half-Blood Prince (film) (First mentioned)