The little pet fish that saved a town in the Amazon

The cardinal tetra is one of the most popular pet fish in the world. They look like little red and blue sequins. You've almost certainly seen them at the pet store or the fish tank at your dentist's office. They're everywhere. Not so long ago, most of the world's supply of cardinals came from just one place. It's a little town deep in the rainforests of Brazil, where locals still catch these fish…