Help with Aggressive 4-Line Wrasse?

Tank is 180 gals, 27 gal sump, 280 lbs live rock, 240 lbs live sand, 2- Ampmaster 3000 pumps, DTSS 800 Skimmer, 3 250w MH & 2 60" VHO actinics @ 11", 2 MaxiJet- 1200 Power Head for circulation.  10% water changes weekly w/RODI water.  Dose daily with B-Ionic for Alkalinity & KH, weekly for Iodine.  Water is 82.4F, 1.021, CA=400, dKH=9.0, pH=8.2, Ammonia=0, Nitrite=0, Nitrate=0. Tankmates assorted. I have a nice Adult Four Line Wrasse about 2.75" long. 

I picked up a beautiful Filamented Flasher Wrasse.  After quarantine I attempted to add the Flasher after feeding and turning off the lights and he was mauled by the 4-Line.  The Flasher goes back to quarantine and recovery.  Any suggestions as to how to acclimate this supposed docile 4-Line to a new tankmate?  Remove the 4-Line to the hospital tank you say?  Great idea!  Any ides on how to capture a fast healthy fish in a reef tank?

The fish trap works great and is available I believe, but I have some questions.

How long has this aquarium been running?
What is the size of the Flasher Wrasse?
Was the Four-Line showing tendancies to be the boss over other fish in the tank?
What kind and amount of natural food supply is present in the tank?
What are the other fish?
What and how often do you feed them?
Is temp constant at 82.4 ? (that's fairly hot, making fish metabolize faster (meaning they need more food) and overly excitable IMO)
How is the tank cooled?

Most fights are over food. My guess (correct me if I guessed wrong) is that your tank is less than 10 months old, which isn't a problem in itself, just that a much older tank typically has a much better supply of natural food. Have you noticed that the Four-line is always cruising and picking for food. It's likely that when the other wrasse was added the Four-line said, "Get outa town cuzin, 'cause there ain't [food] enuf for the both of us." This doesn't mean that the two won't eventually be friends and live together.

Many times a related fish just wants to show the new one who's boss and after that is settled and it finds that the food supply is sufficient for both, there is no more trouble. This, btw is why most public aquarium fish are overweight. They are overfed to reduce aggression.

Now that you've removed the poor Flasher Wrasse, it of course needs time to recover. A decision of what to do with either wrasse should wait on the further discussion I'm sure this forum will produce.

Also, just FYI, 10% weekly water changes are more than recommended. A while back, Instant Ocean's Scientist, Tom Frakes, did a study and found that ideal water change amount and frequency was 10% monthly. I have met Tom and found him to be an honest person. If there was any bias to the Instant Ocean study it would have been in favor of more frequent rather than less frequent water changes. I bet if we did a poll, we'd find the actual frequency amoung us to be more like 10% every two to three months. Anyway, just thought this tip could save you some money.

I hope this helps and it isn't too much all at once. I know it's more than you asked for.
I'm looking forward to hearing more. Welcome to the group.