A friend saw this and naively said something about it being a joke. As I began putting it into context he interrupted saying it's a bad joke if it has to be explained. So he's an idiot and obviously will never get it.
To be clear: The fish is a collectible, porcelain, gold koi fish that's been artfully placed in a porcelain vitrine, i.e. — It's banal, it's kitsch, it references Japanese pop culture, and juxtaposing it with this particular readymade implies that it's dead in the mind of someone living.