So, my sister (against my best wishes) just bought a goldfish and a new tank (if you can call it that). I'm worried that the fish might die soon, because it keeps hovering toward the top of the tank. I can't tell if it's gasping for breath, or not. I don't know anything about goldfish, because I don't have any, so I'm not really sure what to do. Could this goldfish be in trouble? Also, what conditions do they thrive in, and do they need tank mates? Please help!!