Puffer-Fish

• Type: Magical Creature, Potion Ingredient
• Known Suppliers/Storers: Hogwarts student store cupboard

The specific physical appearance of the magical puffer-fish is not described in the novels. They are presumably similar to their mundane counterparts, which are known for their ability to inflate themselves into a ball-like shape when threatened. In the context of Potions, it is the puffer-fish eyes that are used as an ingredient. These are kept in the student store cupboard of the Potions Classroom at Hogwarts.

The primary known use of the puffer-fish is as a Potion Ingredient. However, its properties are highly volatile and dangerous if used incorrectly. The eyes of a puffer-fish are a key example of an improper ingredient that can have fatal consequences. When Harry Potter mistakenly adds puffer-fish eyes to his Wit-Sharpening Potion instead of Porcupine quills, Professor Snape states that the potion has been transformed into an “infallible poison.” This demonstrates that puffer-fish eyes possess potent poisonous properties, especially when combined with the other ingredients of a Wit-Sharpening Potion. The known antidote to this specific poison is a Bezoar. The incident highlights the extreme precision required in Potemaking, where a single incorrect ingredient can turn a helpful draught into a deadly substance.

The only recorded use of puffer-fish in the series occurs during Harry Potter's fourth year at Hogwarts. In a double Potions lesson with the Slytherins, the students were tasked with brewing a Wit-Sharpening Potion. Harry, distracted by a conversation with Hermione Granger about Sirius Black, adds puffer-fish eyes to his cauldron by mistake. The potion immediately begins to emit plumes of green smoke. Professor Snape identifies the error and uses the opportunity to berate Harry, explaining that the potion is now a poison. Snape vanishes the potion and gives Harry a zero for the assignment.

The puffer-fish serves a specific purpose in a single chapter of Harry Potter and the Goblet of Fire. Its inclusion accomplishes two key things:

1. It powerfully illustrates the inherent dangers of Potions, reinforcing that Potemaking is a subtle science and exact art where small mistakes can be lethal.
2. It provides another instance of Professor Snape's animosity towards Harry, as Snape uses the mistake to threaten and humiliate him.
3. The scene subtly reintroduces the Bezoar as a powerful antidote to poison, which becomes a crucial plot point in Harry Potter and the Half-Blood Prince when Ron Weasley is saved by one.

• A Puffer-Fish card appears in the Harry Potter Trading Card Game as an ingredient. (Harry Potter TCG)
• Puffer-fish are an obtainable ingredient in the LEGO Harry Potter: Years 1-4 video game. (video game)