SHERIDAN, Wyo. - Ever since developers learned how to tap coal seams in the Powder River Basin for natural gas, they've struggled with what to do with the brackish groundwater that comes out first. A fish may be the answer. Water is being pumped from coal-bed methane wells in rural, northern Wyoming to John Woiwode's tilapia farm in an area where cattle roam. About 1,300 of the small, pink fish now delight in the water — flipping, flopping and pooping in it. It's the squiggles of poop that interest researchers like Woiwode, and whether that waste could help make the...