That long period of acclimation may not have been the best for them:
http://www.bestfish.com/tips/050798.html and
http://www.aquamaniacs.net/newfishselection.html
I have cardinal tetras because I find them to be more tolerant than neons, and I like the larger size and more red on the body. However, IMO, neons are one of the fish that truly demands an environment more closely related to their natural environment. With soft water and acidic water, they tend to do well. I know many do not alter their pH and I agree if you can avoid doing so.
I think "less adaptable" is a a better phrase to use than delicate when it comes to neons. When you give them what they need, they thrive.
http://www.bestfish.com/tips/050798.html and
http://www.aquamaniacs.net/newfishselection.html
I have cardinal tetras because I find them to be more tolerant than neons, and I like the larger size and more red on the body. However, IMO, neons are one of the fish that truly demands an environment more closely related to their natural environment. With soft water and acidic water, they tend to do well. I know many do not alter their pH and I agree if you can avoid doing so.
I think "less adaptable" is a a better phrase to use than delicate when it comes to neons. When you give them what they need, they thrive.