That big ammonia spill on the Floyd River is no longer a threat to fish. The ammonia entered the water a week ago Monday near Sheldon when a transfer pipe at a co-op broke. D-N-R spokesman Ken Hessenius says it no longer is killing fish.It took the deadly fertilizer a week to travel down the Floyd River, moving six to eight miles a day. He says the ammonia was diluted by the time it entered the Missouri River near Sioux City yesterday. He says the weather allowed the spilled ammonia to stick around for awhile.Hessenius says ice and dry weather, with little water runoff into the river, kept the spill from being diluted earlier. Hessenius says they’re still trying to figure out how many fish were killed.Hessenius says fisheries biologists are still trying to get an accurate count of the fish killed by the spill. That count’s been hampered by the ice on the River. While the ammonia is no longer a problem, the dead fish remain along the Floyd River. He says their clean up is being left to Mother Nature.The fertilizer spilled out when a pipe on a bulk tank broke at the Midwest Farmer’s Co-op near the northwest Iowa town of Sheldon.