I agree with promise, I had a Kole tang that would chase my LMB every time it would see it and thats in a 150g. Sometimes it would swim all the way across the tank at it. The Kole died last year because of hurrican problems and now I have a Blue Eye thats a lot smaller than the Kole was and it does the same thing.
The Blenny is large and is OK but its just stressfull for it you know.
I think any tang in the genus Ctenochaetus ( bristle-tooth/rasping,scraping type mouth ) Like the Kole, Blue Eye, as with promise's freind's Tomini, Chevrons, ect. will act the same way.
I agree its because of the simular feeding habits and competition for the same types of food because the LMB as well as many other blennies have the same type of mouth and teeth design.