Is it normal for comets to line up behind each other and swim right up into the current where the filter flows, get knocked back into the next comet in line then do it again?
They are very active when young (comets are active as adults as well though) so you'd expect this sort of thing. It reminds me of my danios and black phantom tetras. They always seem to swim up against the current and try to get right up to the surface. I've only ever kept small number of goldfish as I don't have a large enough tank (nor a pond) but those that I have owned from a young age did seem to enjoy doing this kind of thing. It's also why I always cover all my tanks - you just never know when a fish may accidentaly propel itself out of the water