Cokeman,
Can you provide us with a little more info about the fatheads you stocked? Specifically, how were they transported (in bags, fish truck, in a cooler)? How long was the tranport? Was oxygen on them while they were transported? Any idea of water temps in the transportation water versus the pond water?
This is a tough time of year to be stocking fish because of the water temps. Just trying to rule out transporting and stocking variables as the cause of death for the fatheads. It would be easy (and probably correct) to assume the same conditions last week killed the new fish this week. However, let's play it safe and rule out the stocking/transporting variables. Also, were you able to remove any of the dead fish from the original kill a week ago or does the pond have rotting carcasses all over the place.
I'm with Ewest in that I would have assumed your DO problem would have already been resolved. Perhaps the stocking info will help us. If not, then it is still possible there are oxygen problems or something bigger going on. Lastly, were you ever able to observe the fish as they were dying? If so, what did you observe (erratic swimming, piping at the surface, spontaneous combustion, etc)?
