Whats the best place in the tank to place xenia as far as flow and lighting, also is it possible to remove them from the little cement frag piece they came on and attach them to one of my rocks?
I would just wait for the xenia to spread rather than trying to remove it from the plug. Honestly an placement, any conditions. In my experience, tank either 'have it, or don't' with xenia. Some people can;t get rid of it, some people can;t get it to thrive. I think iodine has a lot to do with it.
Whats the best place in the tank to place xenia as far as flow and lighting, also is it possible to remove them from the little cement frag piece they came on and attach them to one of my rocks?
Your Xenia will likely remove themselves from the rock plug and crawl onto whatever it is they're laying against. Xenia can spread like mad. Unless you want it everywhere, it's a good idea to put it on a rock surrounded by sand so it can't spread.
Mine got huge, but it didn't spread. It climbed all the way to the top of the tank and sat tall on the highest rock. Maybe it just wanted to sun bathe.
I got my frag on a couiple of pieces of broken rock and it stuck to one of my rocks right away and now....I can't movie it unless I cut it so like Imbarrie says, put it somewhere in the tank where you can let it thrive if it does and at the same time prevent it from taking over your whole tank.