i think some of the more aggressive triggers might bite cords and other stuff in the tank, but i've never heard of any of the Xanthicthys triggers doing it. I've had both a Crosshatch and currently have a Sargassum and have never experienced them bighting anything. They are pretty well behaved. They can get a little aggressive during feeding time, but thats only natural, they just want to eat. Out of all the triggers i would recommend a Sargassum or Blue Throat for a reef they r definitely the most layed back.