COPENHAGEN, Denmark — After waiting two days to find out the fate of nearly 5,000 fish caught in a fire that swept through a building housing Europe's second biggest aquarium, biologists said that more than they had expected survived.

"There is a lot more life in there than we had expected," said Henrik Flintegaard, chief biologist for the northern Denmark aquarium. "There are lots of spurdogs swimming around in there, and mackerels too."

However, the Oceanarium's main attraction, a nearly 200-kilogram (440-pound), 1.8-meter-long (6 feet) sunfish, one of the largest boned fish in the world, couldn't be found.

"We haven't seen it and we fear it has died," Flintegaard told The Associated Press Thursday.

A fire Tuesday destroyed the Oceanarium building and caused two cracks in the 45-centimeter-thick (18-inch-thick) glass which leaked seawater.

The museum, a popular tourist attraction in Hirsthals, 270 kilometers (170 miles) north of Copenhagen, has a 4 1/2 million-liter (1.2-million gallon) fish tank. It is Europe's second largest after the Lisbon Oceanarium in Portugal which holds 5 million liters (1.3 million gallons) of sea water.

By Thursday, the water level had sunk by 5 meters (16 1/2 feet), leaving the eight-meter-deep (nearly 26 1/2-feet) elliptical tank less than half full.

Flintegaard said divers planned to survey the tank to get a better idea of how many fish survived and "to get a full view of the damages."

The museum had been scheduled to reopen after Christmas.

The museum attracts some 280,000 visitors annually. The 100 million kroner (US$16 million) Oceanarium featured thousands of herring, mackerel, garfish and horse mackerel found off the coast of Denmark.