Here's why:
* Oxygen levels: Deep water often has lower oxygen levels, which goldfish need to survive.
* Temperature: Deep water tends to be colder, and goldfish prefer warmer temperatures.
* Food sources: Goldfish are omnivores, feeding on small insects, algae, and plant matter found near the surface.
In the wild, goldfish live in ponds, lakes, and rivers. They are often found near the edges of these bodies of water where there is more sunlight and warmer temperatures.
While they might occasionally venture into deeper water, they do not prefer it and are generally not adapted to living in such environments.