根据短文内容，选择最佳答案。 There is a popular belief that goldfish only have a three-second memory. But a 15-year-old schoolboy from Adelaide has just finished an experiment（实验）to tell us that it is not true. He shows everybody that the goldfish is smarter than we think.
“I don't believe that they had a three-second memory because animals need their memory, so they build up over time a knowledge of where the food is,” said Roy Stokes, a student at the Australian Science and Mathematics School.
He did the experiment in small tank（鱼缸）of goldfish. “I decided to get a bit of red Logo and just feed them next to that. Every day I'd put it in and spread food around it.” He said.
“At first they were a bit scared of it, but by the end of the three weeks, they were actually almost coming before I put the food in.”
After leaving the fish alone for a week, Rory placed the red Logo block in the tank again.
“They remembered perfectly well,” he said.
“They actually had a time faster than the average of the three feeds before I left.”
The goldfish showed that not only could they store information, they also had the ability to get it back as a later date.
Culum Brown, a research fellow at Sydney's Macquarie University, has studied fish behavior for more than ten years.
He says his studies of Australian native fish show fish were intelligent creatures that know how to avoid enemies and catch food like any other animal.
“The thing that I really liked about Rory's experiment is he not only got that classical conditioning going but the fact that he could get them next just to that specific coloured market. I thought it was really good.” He said.
