Thanks for the advice! Currently the blenny is fine, no spots, no tail or fin rot, no mucus, she has a good disposition and is active & alert feeding well, but I will QT her today, just in case.
Just a couple more questions...
Can I use kanacyn to treat for bacterial infection?
The strange thing... nothing new was introduced to the tank, I had the tank up& running (LR
& arragonite sand) for 6 weeks before placing fish in. fish were QT 3weeks. the tank cycled params have been good, not sure how this happened. Fish looked good , healthy & active. I guess I'll have to keep reading. Thanks again for all your help.