My smaller calico faintail has the peculiar habit of swimming nose-up just at the tank surface. She doesn't gasp, so I'm not too worried - she just seems to like balancing and floating/swimming around at the surface. It looks like her nasal septum is out of the water but not her mouth. Is she just enjoying herself, or is something wrong?

Also, the larger goldfish acts like he is NEVER going to get fed again and gobbles up fish flakes fast as lightning. The smaller one doesn't seem quite so concerned and eats at a much more leisurely pace. It is not good manners, but perhaps he is just greedy. I don't remember any of my past goldfish eating so ravenously!

Most goldfish are little pigs! They often act like they're starving when, in fact, they're not. The goldfish who sits at the surface may not be feeling 100%. Gasping would indicate perhaps low oxygen levels (including from high ammonia). Even though he's not gasping, I would check your pH, ammonia, and nitrite to see that they're ok. Maybe he's waiting for more food. It's hard to say. I do know that my three indoor goldfish that I have now (fantails) are pretty much always on the move but, in the past, I had goldfish who would hang at one spot. Increasing circulation with filtration and aeration can help but you don't want to force them to exercise either.