bangai cardinal


Reefing newb
My mom just purchased two of these guys and in the past 48 hours they have not eaten and now one has died. The other one is gulping at the surface but shows no signs of parasites or disease. We found him at the laying on the bottom of the tank, he gulped for about 5 minutes and ended up back on the bottom. Any ideas?
It could be a number of reasons-internal parasites,dissolve oxygen etc.A list of tank parameters and more info would help.I do know the wild caught ones don't do as well as the tank-bred ones.