The idea that goldfish have a 3-second memory is a well-known factoid that isn't actually true.

factoid 是由 fact（事实）加上后缀 -oid（类似...的）构成的词。字面意思是"类似事实的东西"，实际上指"被广泛传播但未经证实的说法"或"看似真实实则虚假的信息"。