We took our 3-year-old son to one of the nation's biggest aquariums at Beijing Zoo on Sunday. It was amazing to see all the marine life, however, I have mixed feelings about the place and I hope my son will understand one day.

Instead of the informative and educational place I had expected, the aquarium looked to me more like an amusement park focusing on making money from eager parents.

Almost all the visitors were parents with toddlers or teenage children. The aquarium wasted no time or space in encouraging the parents to keep spending.

At a big store, stuffed toy dolphins and "Nemos" grinned at young customers, and shirts were printed with cartoon marine animals fit for children of all ages.

I liked a bottle with a cover shaped as a dolphin that was priced at just 30 yuan ($4.30), an average price for such bottles. But my son insisted on a ball which shone brightly and dangled at the end of an elastic string. It was 10 yuan, and my son has got five of the things at home.

There was a narrow winding waterway, where some fish and tortoises were arrayed for visitors to feed with purchased fodder. I don't know much about marine life, but I strongly suspect a child, tortoise or fish could be hurt by the activity.

Please don't get me wrong, I'm not saying the aquarium was terrible. Apart from the heavy smell of business, it was still an interesting place to visit - after all, it is cool in summer and warm in winter.

Most visitors come specifically for the show given by the five dolphins and two sea lions at 11 am every day. I visited five years ago and I clearly remember the pretty narrator's funny lines and the animal actors' stunts - like leaping up to touch a ball some 4 m above the water surface.

I haven't been following the aquarium's development in the past five years, but if the dolphins and sea lions did survive all these years, what boredom they must have suffered from doing the same stunts day in, day out, for about 1,800 days.

Do they get any satisfaction from the audience's lukewarm applause? I don't know. Even if some of the dolphins and sea lions were born in captivity, deep inside, they must cherish a yearning for the deep blue.