I HATE THEM! lol (I really do though)
I bought mine because I had a flat worm issue and some one told me it would be a good idea (I didn't know any better at the time). Okay, it attacked every fish in my tank, literally every single fish. It tore apart the fin on my Coral Beauty, it killed a mandarin (not over food, purely just because it could) and chased my clowns and goby all over the tank. Evil little fish.
A lot of people on this forum will tell you that they're the "fish from hell." I'm pretty sure Florida Joe hates his too.
I was lucky enough to get mine stuck in the overflow, took him as a "gift" to the LFS. Went back two weeks later only for the owner to tell me that the sixline continued to beat on and kill fish in every tank he tried to put it in and eventually sold it to a guy who was putting it in an aggressive tank (I think he fed it to his shark tank to be completely honest with you).
Here's the issue with these guys: Some people have luck, some don't. If you are one of the people that don't have luck with it, GOOD LUCK CATCHING IT!
They will learn every inch of your rock work within 2 seconds of being in the tank and they're small and fast. They're are much nicer wrasses out there