Which of the mosses is the least invasive? I want to keep it in specific area in the tank.

Thanks

Almost any moss can break off a piece and start a new crop in a new place.
Christmas moss has a tendancy to "drape" as opposed to Java which has no set direction in which new shoots go. But any can just be trimmed to suit. Letting it
get very big/bushy will cause the underside aria of it to die off for lack of light so
keeping it trimmed short will prevent this.
Fissidens are a moss which the name of may not come up in a reply to this question.
It grows very slowly so will only invade if you let it. But pieces will break off and
start somewhere else.

Thank you, I already ordered some Fissidens fontanus. I'm making some moss covered covers for my intakes and I was thinking a couple of different kinds of moss would look better but I'm not a big maintenance guy so maybe I better not add anything that needs cropping.