My only concern with Petco is that they put their fish into very low salinity tanks (1.012-16 if I remember correctly) to kill parasites and reduce stress, as they put it. You have to be extremely careful when you acclimate their fish to your tank. I add my tank water to the bag very, very slowly over a good 2 hours vs. the normal 1 hour. That's a huge difference in salinity to account for.
<a href=showthread.php?s=&postid=7754496#post7754496 target=_blank>Originally posted</a> by Mustang394
Lower SG values do have a negative effect on a fihes internal organs as well that may not always be noticable at first. IMO it is never a good idea to keep fish in low SG enviroments for any length of time the internal damage caused by this is almost always permanent. Greatly reducing the life expectancy of the fish.
<a href=showthread.php?s=&postid=7754796#post7754796 target=_blank>Originally posted</a> by COreefer
I agree, long term husbandry should emmulate natural conditions as best they can. However, for the short term treatment and or prevention of parasitic infections, hyposalinity treatments have been proven effective and far less detrimental to the fish than parasitic infection.