Here's why:
* Goldfish grow large: Even "fancy" goldfish, like Fantails and Ryukins, can reach sizes of 8-12 inches. Breeding goldfish requires a tank large enough to accommodate their adult size, not just the size of the fry.
* Breeding requires space: Breeding goldfish involves multiple adults and many fry. A small tank becomes overcrowded quickly, leading to stress, disease, and poor water quality.
* Fry need space: Goldfish fry need ample space to swim and grow. A small tank restricts their movement and can stunt their growth.
* Water quality is paramount: A large tank makes it easier to maintain good water quality. Goldfish are messy eaters and produce a lot of waste. A small tank can quickly become polluted, endangering the health of both the parents and the fry.
Responsible breeding:
* Large tank: For breeding goldfish, aim for a tank that's at least 55 gallons, but even larger tanks are recommended, especially for multiple breeding pairs.
* Good filtration: A strong filtration system is essential for maintaining clean water and preventing ammonia buildup.
* Proper care: This includes regular water changes, a balanced diet, and monitoring for disease.
Remember: It's not just about the size of the tank; it's about providing a healthy and comfortable environment for the fish.