I ♥ BBA!
As I've been sewing again, I've noticed a new trend. They are adding more and more fire retardant chemicals (mostly polybrominated diphenyl ether (PBDE)) to the bigger name brands of quilt batting and pillow stuffing. Be sure to look at the contents before buying it to use for your fish tank. They'll list it some where on the bag most of the time, but not always. More and more of the cheap brands are going this route. Rinsing it will often not get rid of it as it is embedded in the fibers.