If you mean are grammodes aggressive? Yes they can be hyper aggressive, and tend too be loners. In nature they may also hide a majority of the time and are lurk and strike predators, that remain under cover until a prey item passes, then hit, lightning fast, and go back to their cave, or selected spot.
Mine were usually only out and about, when guarding a school of fry.
This attitude can can be changed if time is spent acclimating them from a young age to your presence.
They, or Cubans may or may not bother plecos, it seems to be an individual personality thing .
My male Cuban, topped off around 10", and the female 6". Before I gave them away, they spawned at least 3 times, which at times, slows growth (especially in females) due to energy transference from growth, to eggs and fry.

grammode pair above.
Cuban female below
