I had the same thing happen. I used a drop of super glue gel and glued it back to the frag plug it fell off of. make sure you glue the right end though.
180g Reef - 60g Rimless Reef -90G FOWLR- 125g Malawi Cichlids- 40b REEF- 34g Fresh Planted-working on- 20L FOWLR- working on
I have a mix of many different saltwater fish amongst my tanks, but I love my Tangs most of all.