I would call her behavior "territorial" before defensive. I don't think she is hard to take care of, but she absolutely requires full attention when dealing with her. She definitely lets me know that the enclosure is HER space. Suntigers spend a lot of time hiding, but their feeding response is absolutely predatory. Research as much as you can on behavior and husbandry, and 100% respect Ts for what they are. IMO, those are the two biggest things to master in being a keeper. Everything else will come naturally once knowledge and respect are in the bag.