Common Goldfish (Carassius auratus)
* Average: 6-12 inches (15-30 cm)
* Maximum: Up to 18 inches (46 cm)
Fantail Goldfish
* Average: 8-12 inches (20-30 cm)
Comet Goldfish
* Average: 12-18 inches (30-46 cm)
Other Varieties:
* Oranda, Ryukin, Telescope, etc.: Can reach sizes similar to Common Goldfish.
Important Factors:
* Tank size: A larger tank allows for more space to grow.
* Water quality: Poor water quality can stunt growth.
* Diet: A balanced diet contributes to healthy growth.
* Genetics: Some varieties are naturally larger than others.
Overcrowding:
* Goldfish are prone to growing larger in larger tanks.
* Overcrowding can lead to stunted growth and health issues.
Keep in mind: The lifespan of a goldfish can be 10-20 years, so they can grow quite large over time.