Hi Beeba -
It's about 3", that's way bigger than life
Beautiful, wonderful fish. I only have one, I've always heard of them as difficult to keep.
A few reef friends have had no luck with them, but with my 58 with only a Midas blenny, couple of masked gobies, and a green clown goby last winter ... I figured I had a `mellow' enough tank for one. The local LFS had one for a few months, I had trade-in credit from frags, and the rest is history. Very shy at first, took a month of QT to have it eat when I was close + watching ... but it's out most of the time now, a beautiful `feature fish' for a smaller peaceful reef IMO.
But hard to get a healthy one I hear [thus waited for one to be `hanging around' at the LFS for a long time] ... and I do violate some of the suggestions [it's a brightly lit tank] - but it's done well and I'm quite happy. I'm going to have to avoid stocking fish that would compete with it, want to hang in it's spots, etc ... but I'll do that for one as stunning as this.
Hoping for many happy years together