In my 30+ years of keeping marine fish, what happened yesterday has never occurred. I look at my 120 reef last night after feeding and my 14 y o purple tang has a rubber band around his entire body. I use a rubber band to secure seaweed to a small rock on a string for my tangs. Seldomly, I’ve noticed that they’ve pulled the rubber band off the rock, and left it in the tank out of difficulty getting to it among rocks. I remember my big blue tang passing a rubber band from anal cavity a long time ago, but nothing like this! I’m thinking of using the clip I have, but they pull the whole piece of seaweed off of it and it makes a mess. Anyways, I was able to net him and as I attempted to remove it, it broke, which I think would have happened eventually, but I didn’t want to take chances. It didn’t look good.