Scaring fish straight!

The 35,000 sardines in the Kuroshio Current Exhibit at Nagoyako Aquarium (Japan) were once well behaved. They grouped themselves in a coordinated school, creating a "pilchard tornado" - a massive whirling ball of fish that delighted aquarium-goers. But as time went on, the sardines began to break formation. Aquarium officials had to do something to get their fish back in line.