How big should a goldfish get?

Goldfish size can vary depending on the species and their environment. However, here are some general guidelines for average goldfish sizes when properly cared for in appropriate conditions:

1. Common Goldfish (Carassius auratus):

- Single-tailed varieties (e.g., Comet, Shubunkin): Can reach lengths of 12-16 inches (30-40 cm)

- Fantail and other fancy-tailed varieties: Typically smaller, with lengths ranging from 6-10 inches (15-25 cm)

2. Fancy Goldfish:

- Veiltail, Oranda, Lionhead, and similar fancy goldfish varieties: Generally smaller, reaching lengths of 6-8 inches (15-20 cm)

3. Crucian Carp (Carassius carassius):

- Closely related to goldfish and sometimes kept in ponds: May reach lengths of up to 18 inches (45 cm)

It's important to note that goldfish have the potential to grow larger than average sizes in ideal conditions, particularly when provided with adequate space and proper care. Providing suitable water quality, ample swimming space, and a nutritious diet are essential to ensure healthy growth and prevent stunting.