Diving yesterday but attacked by Titan Triggerfish

Yesterday I had two great dives again.
I am not sure that I have mentioned the Titan Triggerfish before, so here is a little bit of information.
This fish which can measure up to 80 centimers in length and which is equipped with some pretty scary teeth, can also be highly territorial and aggressive, not least in the nesting season.
It is not uncommon for divers to get bitten around Koh Tao - usually the dive leader get the bites since he is front or since he will go between his or hers divers if a triggerfish appears.
Yesterday I noticed one triggerfish, and I tried to avoid its territory. But I did not see the mate, which was already attacking me from behind. I used around 5 minutes, using my fins and my metal torch to to hit it in the head. But this one was highly persistent. Luckily it did not bite me.
This was not first time I try this at all, but the trigger fish yesterday was particularly territorial and aggressive. Usually the trigger fish will give up the fight if you move out of its territory. However, there are examples of some pretty nasty bites.
You will find a few photos (from internet) of this fish, as well as some nice photos from the dive boat on the way home