I just observed this "thing' one of my bristles did.
I got a tall octagonal tank. The bristle would scale one side of the tank wall until about 5-6 inches from the surface, then did this BIG back flip across the tank, nearly touching/touched the surface with its mouth, almost touched the opposite tank wall, then it went back to the original tank wall where it began the "flip" about 5-6 inches below the level where it flips. then it'll scale up the wall again, back to the 5-6inch-below-surface-level, then did the back flip all over again!!
I watched it did the back flip 7-8 times in a row! what the?

Just observed some more, and noticed several variation on the big "flip" e.g. skims the surface with its mouth, pauses on the other side a bit, and a few more things, but basically still doing the big-across-the-tank-then-back-again back flip

Bristles are crazy little buggers! Wait until he disappears,and you finally realize that he crawled up and into your filter!!!

Is there enough oxygen in the tank and is he getting enough to eat?
None of my bristlenoses do that but my spot plec does when he wants fed.

i don't know,I've caught my Common Plec's many a times pulling crazy stunts like that.They're pretty big too,so when they do it,they really do it.Out of all the Bristle's that I own,only the Albino Male does crazy things on occasion(Like swim up into my filter,not once,but twice!!! He was looking for a breeding place. I have strong filter's and lots of aeration,so who knows???

I got lotsa aeration & curent going thru the tank, and now after the bristles know that zucchini is food, I swear they've grown a bit already since i got them 3 weeks ago.
one of my my bristles' fave hang out place is the casing of the internal filter dunno why. they would also intentionally stick themselves among the aerator bubbles and kinda "slide" up the tank wall backwards

funny litlle buggers