Manny's goldfish

Manny's goldfish was the fish Manny bought in Diary of a Wimpy Kid (online), but in Dog Days, he bought fish food, by the time they got home, Manny had eaten half of the canister.

Online Version
In Diary of a Wimpy Kid (online) after Greg’s birthday, Charlie Heffley took them to buy pets Rodrick was looking at a snake, while Greg and Manny were looking at fishes, but Susan Heffley told Rodrick it was dangerous and forbade him. So Rodrick took an aggressive fish while Greg got an Angelfish and Manny got a goldfish. Rodrick's Fish soon ate Manny’s goldfish and attacked Greg’s at the same time.

Trivia

 * In Diary of a Wimpy Kid (online), Rodrick's Fish eats Manny’s fish whole.
 * It does not appear in the book, due to Manny only buying fish food for himself.