Fish Gone Missing

As Zhang Zian explained the differences in artificial sea salt, everybody listened carefully. Only Welder Zhao grew impatient and said, "Useless talk. This is a waste of money! When I started my saltwater tank, I didn't spend a cent. And the fish are thriving!"

"What? Mr. Zhao, you didn't spend anything on your saltwater tank?" Electrician Wu paused in surprise.　　

He knew that Welder Zhao was a saltwater aquarium fan and had started earlier than him. He checked it out at his place and felt they were nice. The tanks were big, with bottom sand and eco-bio-blocks. It looked very decent, but he could not imagine that he didn't spend money on it.