Not my own doing but; The first dragon goby I purchased was dropped into a tank with a dozen GSPS and lasted about a minute, I am told. Since it was killed a mere hour or so before I came to see if it arrived I ordered another and insisted they just leave it in the bag and call me as soon as the fish shipment arrived.
The "replacement" arrived, I was never called, and he met a longer version of the same fate.. The second was dumped into the same tank, however, some of the puffers had sold. All of his fins and some flesh were torn off. My thoughtful husband knew it was fish shipment day so he went to pick it up while I was at work even though no one called. Long story short, he called me to say he got it and I got excited since it WASN'T in the puffer tank when he picked it up, then he brought it home and realized it had BEEN in the puffer tank.. No fins whatsoever, no tail, open wounds covering most of his body. Called the store, brought it back the next day barely alive for my refund. They people there were potheads and going to leave it on a counter, I stuck him in their food freezer at least.
The third one got lucky, I applied my refund to a replacement and again, came in the day of shipment. They didn't call and it was almost store closing time but among the 50-some bettas still in tiny bags I saw my dragon fish. If we hadn't been there he'd have been left another day or two with the bettas.

I almost wish I bought one from walmart sometimes..