The only fish I've lost so far was my first fish. It was a clown fish from ***** for $18. It died a day later. I went back in to the store later that night with my brother to pick up a couple things and all the fish in the tank it came from were half dead, or dead. I told the manager it was BS and they let me get a Maroon clown. The maroon is now in my brothers tank, because he wouldnt give it back. Put it in his because I was about to be moving. He gave me $20 for it, so I made $2. He still has it.
I've lost an anemone that was $8, my first peppermint shrimp, which was actually still alive when I flushed it. It wasnt moving til I put it in the toilet and I wasnt about to fish it out.....
I also had a huge hermit crab I gave to my brother, and when I was out of town he put it back in my tank and it ate my cleaner shrimp. I took him to the LFS and told them they could have it.
I did have some zoos that have now vanished. I cant even find the rock they were on. Kind of upset about that.