Could someone identify this please?

[Pnutjr]

Hello all,
I've been reading at Canreef for a bit now and everyone is very informative. Thanks! I recently got an established (at least I thought it was) 55 gallon tank. After setting it up with only one lost Tang , my wife found this as in the pic. Its purple with white banded stripes on every tentacle with white tips. I thought it was a bonus. Now I'm thinking its gonna be a nuisance. Any thoughts anyone as to what it is?? Thanks

Pnutjr

55 gallon, 30 + lbs live rock, Perc Clown, Fairy Wrasse, 2 Blue Damsels (mean little suckers), Lawnmower Blenny (somewhere), Cleaner Shrimp, Red star fish, 2 Hermits and 4 common snails