I love Gold Nuggests. I've tried 2 and both died relatively quickly. They're one of the harder plecs to keep and I'm debating when to get another. I *will keep trying until I get a healthy one.
Edit: Forgot to even tell you sorry for your loss! I do know how you feel.
I know that there are several different species that are all referred to as "Gold Nuggets." They do vary based on different spot sizes, growth potentials, etc. So, I wouldn't be at all surprised if one species or another is more adaptable to aquarium life.