Goldfish have actually been shown to have a 3 month memory, they are so smart they can be trained to swim through mazes or push a ball through a hoop.
When kept in bowls they suffer from stunted size, mostly due to the fact that goldfish pee a lot, without a filter their tank gets dirty quick, basically they do not grow because they are swimming in toxic water.
For some stupid reason people seem to think that goldfish, which can grow up to 12 inches or more, are okay in a tiny bowl, for their tiny life. Speaking of tiny life, goldfish can actually live for 20 years, so they really are more of a long term commitment than people think.
This has become such an issue that Rome has banned people from keeping goldfish in bowls, and many areas where they use to be considered carnival prizes have banned that idea too - yeah.
Gold fish are real living things, they are animals, they deserve better treatment than to be kept in a filthy, tiny bowl devoid of anything even remotely considered interesting.
If you want a pet that requires no care, and no space, get a pet rock. If you want a goldfish you need to provide it with the right size tank, this can even mean a 30 gallon tank for just two fish. Goldfish were not meant to be stunted, they were meant to grow and live full lives, deal with it.
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Why is my Goldfish not Eating?
Types of Goldfish