I am trying to decide what trigger to get, A Blue Lined or an Undulated. I am looking to only have that one fish in the tank and was just wondering what you guys recommend I get. I am looking for something that is extremely mean. Everyone I talk to says to get an Undulated trigger but I have never seen one except for the picture on the one on this site. On the toher hand I have owned a Blue lined which unfortunally died and I got to say that it is a really nice lookin fish. But as far as agressivness goes, how agressive do blue lines get?