Aw I'm so sorry. Nitrates are usually all right below 30 but what is confusing me is that you hadn't cyled the aquarium yet and were getting nitrate readings. Nitrates means the cycle is done. I don't trust test strips because they can be extremely unreliable depending on how they are stored.
You acclimatize him properly, I thought you would :)
It sounds like you got a sick fish, you tried very hard and did everything you could, I commend you for it! Maybe now you can cycle the aquarium fishlessly and then, once it's done, you'll feel up to getting a new friend?
Once again I'm really sorry.