Help With UI/Addon

I've recently started playing again on Icecrown and I'm not sure how to modify my UI. My UI is always filled with bars over people's heads and sometimes enemies but not every enemy? I've included a screenshot so you can see what I mean because I'm terrible at decribing it as you can tell. I can't remember if this is an addon or a normal UI feature as I remember it being very useful during raids and such from when I used to play before but now it's making the game much harder to play so if you know where I can modify this stuff I'd really appreciate it. https://imgur.com/a/7WAEQNf

Edit: I figured it out after some more digging in settings lol