sixline wrasse, you can ask around and get two different opinions like their not aggressive or their semi-aggressive. Still its a good fish, i never seen when my 180 was running with corals that there was any aggression at all and tank size as well will play a hugh part in aggressive behavior from other tank mates. Perhaps you not mind taking a look at the Yellow Wrasse (Halichoeres chrysus),. it would add color for your F/O tank. Another type of fish you might like to take a look at are the Blue Spot Sharpnose Puffer, Saddle Puffer Fish and the White Spotted Sharphose Puffer as well there are a number of others in this area you could take a look at, even the Valentini species of this family, but you can only select one. And also check around asking others for the one that would be the lease aggressive.
research you must and never say your sorry, for note that we all can learn some things from each other at one point or another. Also, be careful from were you research your facts at, facts can and often do differ from one site to another, start taking notes and look around to what other links tells you to those facts you found. You will come to learn to which links you can trust over the others. And do know that just because your reading a writers article, it not make that person all so knowledgeable. I seen many writing articles on all type of eels and found that person facts was only based on a few weeks of research. For most of the main facts he listed in his article were false.
So what if it be on the Internet or from a book as well as from any forum link, its that persons opinion and nothing more, it takes time of assisting one time and time again and only when you see that person who suggested such matters to you and been right on the money, you come to always trust his or her opinion. One final note, I been in this hobby for more then 60 years and im still learning things today, I will be learning until the day I die.
Buddy