Goldfish

Goldfish are Critters that swim in water, and walk on land during Rain. They can be caught with the Bug Net and used to craft several items. They can be spawned from the Fish Statue.

During a Blood Moon, or when hit with Vile Powder or Vicious Powder, Goldfish turn into Corrupt Goldfish or Vicious Goldfish, which have much more health and do attack players. This can be confusing for new or inexperienced players, as Goldfish are seen as passive.

Trivia

 * While not directly utilizing the trademarked phrase, the Goldfish's tooltip is a reference to the snack food Goldfish ("the snack that smiles back").
 * Goldfish could previously be killed and then used as a weak recovery potion (restoring 20 health), which the tooltip is a remnant of.
 * Goldfish have black eyes, but when killed have red eyes. This may be because of the blood that appears when you kill it.
 * The way Goldfish walk on land during rain may be a reference to how fish walk on land in several Dr. Seuss books.
 * The Goldfish, Bunny, Bird, and Penguin are the only four Critters that have banners of themselves.
 * On the, a cloud in the shape of a Goldfish can occasionally be seen in the background.
 * In real life, goldfish do not walk on land, as they cannot breathe when taken out of the water. This shows that Terraria Goldfish are likely not the same creatures as real world goldfish.

History
Goldfisch Poisson doré Złota rybka Peixe-dourado Золотая рыбка 金鱼