When a new fish dies...

[mpderksen]

First off, I don't have a QT. I know I should, but I get so few fish I just never have.
I brought home a new foxface Tuesday. He got pestered for a few hours by the Maroon, no surprise, but settled in pretty quick. He was out, eating and colorful the next day. Thursday he was in a cave all day, and didn't come out much. Friday morning he was dead. I also picked up a new cleaner wrasse at the same time, and he's doing great.
Water tests are fine, and yes, I drip acclimated.
Does this just happen? Or is something in my tank suspect. Nothing else from this LFS has died on me, and they keep very clean tanks.
Am I guilty of killing him with a bad environment in some way? Could he have not been at the store and this would have happened anyway?
Is it better practice to purchase another, but leave him at the LFS for a few weeks after I pay in case he just came in? I think they treat with low level copper, which I can't confirm and know nothing about.
The only 2 fish left to complete the tank is a foxface and a kole tang. Would I be better off using love aquaria?
I'm nervous because this is my second foxface to die. The first was in February after I did a 3-day blackout to tackle some GHA. I also dosed AlgaeFix at that time, so I waited and have done a lot of water changes since then. She was several months old.
I'm not going to keep putting fish in there to die if there's reason to think there is something wrong with the tank.
But all the other fish have been doing great since last fall.

[Paul B]

It does happen sometimes and that fish may have died in the dealer's tank. If you go to a LFS when they open up in the morning much of their time is spent removing dead fish. Many of their fish come in dead as being collected, stored in a shipping facility, mailed, then being stored again at a wholesaler and then in a store frequently kills fish or puts them in such a state of declining health that they will die shortly. If the rest of your fish are fine, don't worry about it.

[ca1ore]

Paul is correct of course. You can take the most extreme precautions possible, be completely OCD about acclimation and QT, and you will still occasionally lose fish - though almost certainly with less frequency. Sometimes a fish dies, it's not always clear why, but collection and shipping stress are as good candidates as any.

[julie180]

What size is your tank? Maroon clowns are one of the most aggressive and even though you don't see it, they can harass new tank mates to the point of death. I had a coral beauty that killed several new additions before I figured it out. I never saw the problems and the fish looked fine before and after they died.

[mpderksen]

It's a 75 gallon. Yes, she was pretty aggressive at first, even though it seemed to stop after a few hours. The foxface initially though the perfect spot was in a cave right next to her nem, which was obviously a bad idea.... Once she found the other side of the tank, all seemed well.
The Maroon is fairly small, maybe 2". I know they can be aggressive. Maybe I move her, add the new foxface, then move her back in a week or two? I do have an empty, cycled nano that she could hang out in. Of course, the trick would be catching her....