阅读下面短文，按照句子结构的语法性和上下文连贯的要求，在空格处填入一个适当的词或者使用括号中词语的正确形式填空。

I have a friend. name is Happy Day, but everyone calls him Happy. Happy (travel) widely. When he comes to a new place, he opens a pet shop and starts (sell) African Ghost Fish. Happy often tells the story: “These are the only invisible(看不见的) fish in the world, and they need no food. Once a year, the female Ghost Fish lays eggs. Then, while everything is quiet, she becomes visible. addition, she's(beautiful) creature in the world.” After Happy tells his customers this story, his fish tanks(鱼缸) sell very (quick). They become much (popular) than before. When Happy sells out of fish tanks, he usually leaves and starts selling fish tanks in town. He has rarely received a complaint(投诉) since he began the business. In fact, many people take pleasure in (look) at their invisible fish with their friends. Sometimes, people are too dependent on something new because their curiosity(好奇心).