Elizabeth River, Virginia, USA is contaminated by creosote, pentachlorophenol, and other chemicals used by a nearby wood treatment plant. Normal killifish taken from clean rivers die there, and killifish residents of Elizabeth River die when placed in clean water.

They have adapted to the conditions, and their offspring inherit the adaptions - Office of Naval Research press release

“These fish have apparently become acclimated to the contaminants, perhaps through altered expression of certain genes, and their progeny apparently inherit the ability to tolerate these conditions, too. There’s some very interesting science going on here.”