I have a full grown male and he digs like crazy. I can here him at night thrashing around making the tank how he wants it. Just wondering if anybody else's plecos did this because this is the first time I've had one do it.
Yes, they will dig if they haven't got a suitable place for breeding. I presume that you have a female bristlenose in the tank, her hormones (feromones?) would make the male more active. But my guess is that the male will dig anyway, even if there's no female around.
Mine dug out a cave twice, and when I tried to be nice and give him a good cave, he pushed the eggs out [could be "badly designed cave"], so I let him do his own for the next time... At least then he has got a cave to his liking.
Just make sure that the digging won't undermine any structure in the tank so that it falls over or something...
I have an albino bristlenose that digs like crazy. He is in a tank with an unidentified peckoltia and a blue ram. This tank is in my bedroom and unfortunately there is gravel bouncing off the tank walls throughout the night. I don't know why he does it--hopefully not attempting to make a nice cave with the peckoltia.
Both my Panaque maccus (L104) and my
Pseudacanthicus leopardus (L114) dig quite a bit.
The Panaque digs in the sand where a piece of bogwood rests on the sand, and ends up almost underneath the wood out of view. It's surprising that he can move nearly as much sand as the bigger L114 shifts!