In reverse chronological order:
Auratus: The water in the tube is oxgyneated, so they can breathe in there, no problem. The tube is also many times wider than the fish, so I'm fairly sure they won't get stuck. The only way they'd get stuck is if they all tried to go through the pipe at the same time, in which case I don't think they'd fit in the pipe to begin with. But if you are going to worry about that, you might worry about them getting stuck under a rock too
mr_broken: Thanks
sunbot: The suction thing is actually for my worm feeder, not for the tubes. It's easier to throw the tubes right in front; I'd rather not move things around if I don't have to. Also, it makes it easier to see them playing in the tubes
Thanks for the suggestion though!
And on a side note, they hang out in the ring all the time now. Especially when the lights in my room are off and the lights in the tank are on (then the loop is probably the darkest part of the tank). They seem to love sliding down the sides of the tube and then swimming back up
Hope you all enjoy the vid!!