Facts about Goldfish

1. 06

   Carassius auratus possess a specialized esophagus that can expand to store food, allowing them to consume up to 10 percent of their body weight during a single feeding session.

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2. 05

   Oxygen deprivation in goldfish can be survived for up to 5 months if they enter a hibernation-like state in freezing water without oxygen by metabolizing glucose anaerobically.

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3. 04

   In 1956, William T. Innes documented that goldfish produce audible sounds through their pharyngeal teeth, creating croaking and grinding noises during feeding and spawning behaviors.

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4. 03

   Goldfish can grow up to 16 inches long in optimal conditions, though most aquarium specimens remain under 6 inches due to stunted growth from inadequate space.

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5. 02

   Selective breeding of goldfish in China during the Song Dynasty produced over 125 recognized color varieties by the 1600s, establishing them as ornamental fish centuries before European popularity.

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6. 01

   Three seconds is the memory span of goldfish, a misconception since they can remember training for months and recognize feeding times.

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