I bought an oranda on Sunday afternoon for my newish pond. He wasn't very active in the tank, but my daughter really wanted that particular one. He flopped over on his side when they put him in the bag, but eventually righted himself. I KNEW I should have said nevermind. I put him in the pond (yes, I floated the bag for a while and added Stress Coat), and he went straight to the bottom. A few hours later, and he was on his side. The next morning, he was on his side again, but in a different spot. I retrieved him with the net, but he was not dead...still moving just a little. Today, same story. I called the aquarium store, hoping they would offer to take him back (48 hrs is their guarantee), and they simply said they thought he was stressed and I should use salts.
Any ideas? In my experience (with indoor aquariums), they don't "come back to life".