after gettin my tank set up, i put about 4 or 5 doz minnows in it left over from our last trip. cut the aerator on and covered the tank. went out yesterday to check on em and all of em was floating on the water. I dont know what killed em, but they must have died right after i put em in the tank as they had been dead awhile. the water is well water with no chlorine, the tank is a 100 gallon galvanized metal stock tank so i was wondering if maybe it was the river rock.. i put two bags of that in the bottom. maybe they are washed in somekind of chemicals or acid that killed the minnows.. the water is cool and i dont think theres no way that few minnows would die in a tank that large in just a couple days. the water had also turned a milky color.. anybody got any ideas on what happened?