The arapaima (air uh PYE muh) is one of the largest freshwater fishes in the world, growing up to 10 feet and weighing 330 pounds. An aggressive hunter, it prowls floodplain lakes, gulping fishes and insects. Many fishes have trouble surviving as lakes' temperatures rise and dissolved-oxygen levels fall, but the arapaima thrives because it breathes atmpospheric oxygen through its mouth.

For the arapaima, low-water season is a time of gorging and building fat reserves that will nourish it during the floods, when prey are dispersed through the forest and hard to find. Historically, the arapaima has been hunted throughout its Amazon basin range for its scales and rasoy tongue, which are used for tools, and for its tasty flesh. Due to heavy commercial fishing, arapaimas, especially large ones, have become rare.

From Amazon Rising: Seasons of the River. Shedd Aquarium.