Japanese chef Kai Kosei offers dishes featuring "Zako," fish with little or no market value. Either because they're too small or aren't commonly eaten, they're mostly discarded. In response, Kai's restaurant celebrates their deliciousness, serving unfamiliar fish like mottled spinefoot or Roudi escolar as sashimi, or deep-fried Luna lionfish. His Zako cuisine is a hit. And due in part to his efforts, these once "useless" fish are now regularly seen in the fish market.