The newest additions to Shanghai Ocean Aquarium's Shark Bay aren't the docile fish they were once thought to be.

Now the aquarium is trying to integrate the vicious bull sharks with others.

The aquarium never intended to buy bull sharks, but bought the four carnivorous fish by accident.

As they were only a few months old when they were caught, the bull sharks still looked a lot like gray reef whalers — a friendly species of shark that lives near coral reefs.

After they arrived at the aquarium in September, feeders soon discovered the sharks were much more aggressive than expected. They also had short snouts instead of long ones that are usual with gray reefs. Experts finally concluded they are bull sharks.

An underwater net has been set up to separate the bull sharks from other residents in the aquarium's "Shark Bay." The bull sharks are under constant surveillance. Special meals are designed for them to ensure they are never hungry — a situation that can have dire results.

Their daily meals include cod fish and sleeve fish, according to Xu Zhiguo, the bull sharks' feeder.

"Each bull shark's meal portion is calculated based on its weight," said Xu. "We have to ensure they get full every time."

Hunger or intense stimulation can make bull sharks vicious. Xu said the aquarium is trying the best to avoid the two conditions. Since all of the sharks are under one year old, they might be just as tender as the gray reefs, Xu said.

The aquarium will soon remove the net and let the bull sharks join the others, according to Wang Hong, the spokesperson at the Shanghai Ocean Aquarium.

(Shanghai Daily December 20, 2005)