my ryukin is behaving awkwardly
 

firstly, for some reason my fish open and close thier mouths a lot more often. secondly, my ryukin swims to the bottom of the tank. then after a while he sharply speeds his way to the top of the tank to the point here his face is out of the water. when he comes back down his mouth is closed tightly and then he breathes bubbles out of his mouth. Is he just collecting air or should i be worried about this? thanks.

i would assume they aren't getting enough oxygen in the water.

What are you water parameters? Ammonia, nitrite, nitrate? My guess is he's suffering from poor water quality and having trouble breathing.