Yep bag water was 7.4ish which matched what I was told they were in, they were in the bag for approx 45 mins journey, then 15 minutes floating before I did the add cup of tank water/ cup of bag water out method which I always use.
Shelagh, sounds interesting, I didnt bag the fish and I didnt look that closely, each species of cory was bagged seperatly, the pandas in their own bag so I wouldnt have noticed that. I know that panda corys are more sensitive than many of the other species of cory, funny thing was they were the most active of all of them, always out looking for food and I think eating more than their fair share and the other 3 still are!!
Probably never know what it is, but I shall do daily water change for a while, have been doing every other day since they arrived,once was to clean up plec poop before I moved her to her own tank (she came with the corys from same source), then yesterday again just as I was doing all the other tanks anyway, but I shall just keep it up for a while, dont want to lose anymore/
Thanks again Wilder, anything else occurs, i shall let you know.