I believe that your blue line is just as aggressive as an undulated trigger. By the way, beautiful trigger that blue line. I have a small undulated I got for $15 at a crappy fish store that was moving (they didn't even know what it was) along with a tiny picasso for $5 that ended up dying within a few hours (had to try and rescue him). The undulated has not touched the urchins in my pond, or even the xenias that have been sent down there. In fact, he spends a great deal of time hiding in the rocks, even though he is the lone fish in there. I think that undulated triggers are fairly aggressive, but that they have gotten kind of a bad reputation in the fish trade. On my honeymoon in the Tahitian Islands, I saw many many undulated triggers, and they lived peacefully with the other fish on the reef. I never saw them bite anything, and in fact, I'm probably pretty lucky they didn't bite me, because, naturally, when they disappeared into holes, I just had to dive down and peer into the holes and poke my fingers in there to see what else was in there. Probably the only thing I saw them eat while snorkeling (and trust me, I spent a lot of time snorkeling to my wife's chagrin) was plants floating by that they would sample.
