I know this is a little late, but it may help other people as well. Did you Q.T. your live stock before letting them run? If so how long did you Q. T. them? They should be quarantined for at least 30 days at over 75. A careful eye on them during this period to avoid headaches like this helps. I use to not Q T fish & would get lucky sometimes but more often than not I would get trouble!