Originally Posted by Six
To keep this scientific and not simple subjective theory- can you eleaborate more on when the fish was bought, how many, and what tank size and establishment/chemistry you introduced them in?
Without having kept notes I can't elaborate much. The QT tank was a bare bottom tank, about pH of 8, maybe 7.5. I don't remember if we mixed RO/DI water in with it or not, but I think we did to get it close to the water the incoming fish were used to. I used Amquel Plus as a "just in case" thing. We added floating plants from the goldfish aquarium. The store's pH was not far off from our pH.
I do remember that deaths from a Chillicothe store that rhymes with "wetland" died off much faster than from a Grove City store that rhymes with "get Smart." We had much better success from the latter store. Some losses, though. Zero losses after we put them in the established, planted tank, with the exception of one time when I think we did lose one.
The QT tank was 10 gallons, the final tank was 55. The numbers varied from 6 up to 20, depending on how many I could afford at the time.
If I did this often I might have done some data gathering and ran it through Minitab to see what correlations there were between different variables, but I did not. I used to do that for a living (six sigma) and I've been away from it for a while and got lazy about things like that.
I'm sure that what the fish have experienced before taking them home is a big part of the problem. The second store mentioned before holds them in a warehouse for a couple of weeks to weed out the weak ones (and possibly to spot serious problems). They have a system in the store that changes water in the tanks several times daily.
The ones I got from Matt (3?) all survived. They were placed directly into the 55. Of course, they came from a clean tank and didn't have all of the stresses that store bought fish might be subjected to.
From now on, with these fish, I'm just going to check all of the tank inhabitants out carefully before buying any fish from that tank and will place them directly in the 55. We still can use a few more of each of those fish species.