Animal Stories - Undulate Triggerfish

Animal-World Information about: Undulate Triggerfish

   Even though he's a beauty, this guy has the reputation of being the most aggressive triggerfish! Which means the Undulate Triggerfish or Orange-lined Triggerfish may be the most aggressive fish, period! Actually they are okay when they are small, but get cantankerous as they get older.
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AR - 2009-03-13
I have an Undulate Trigger living with a Yellow Tang... they have been together since they were babies and believe it or not they are best buds... every now and then the tang will cross the line and the Undulate gets a little nasty but the next day all is well. What I find most odd is the Undulates behavior of building... this guy will literally move all of the sand, gravel, rocks and coral in the tank to one side... he builds these huge mountains on one side of the tank and leaves only the glass on the other side... each time I go in to clean the tank I level off the sand and gravel and move the rocks back, he goes crazy and starts attacking me... than within a few days the mountain is rebuilt... I have had saltwater aquariums for years and have never encountered this behavior.. it's amazing to watch him work tirelessly and I am actually starting to feel bad about re-arranging his home...:-)

Click For Replies (1)
  • Anonymous - 2011-05-17
    He is building a place to sleep. You need to provide a cave for him.
steve - 2011-01-26
I had an undulated with a yellow tang, a lion fish and a very fast damsel. When the trigger got mad he would actually change colors, kind of an electric blue striped brown color. And I swear when he got really mad he would grunt or bark at the other fish. I called him cave boy because he only came out to kill something. I eventually returned him for a huma, much better tank mate.

LC - 2010-12-20
I got a 5-6"ondulatus trigger! He ate a 6" panther grouper,5" niger,4'5" picasso! He's a beautiful KILLER! They were in a 75 gallon tank! Got along all together for about 2 years till one day he decided to be alone! Within a week he ate the other fish! He's been alone for about six months now! I'm working on getting a nice size lion fish! Can't wait.

Nichole - 2010-04-08
I just bought a undulate along with a blue tang. They are about the same size and seem to get along so far. I also have a snowflake eel and they are funny to watch. My undulate has kind of set the tone for what's "his," but now has settled in. I am hoping if I keep him well fed it will keep his aggression under control. I did not know that they were very aggressive fish until after I bought him. So we shall see how it works outs.

NP - 2009-02-15
I have an undulate trigger and a picasso with a foxface rabbitfish, coral beauty, and two clown fish. So far there have been no deaths but the undulate is very aggresive. No one dares go into his cave or there certainly would be a death. The picasso used to rule the tank but now he just stays out of the way and sleeps on the other side of the tank, not anywhere near his old cave (the undulates new home). The undulate also has nipped a lot of the tail from the coral beauty. Like other people said, very aggresive but also interesting and pretty.

Rob - 2008-06-09
I had an undulate, about 4 inches, in a 75 gallon with a similar sized picasso, niger, and a 16 inch wolf eel. Well, I fed them more than the required amount daily, and he still ate the niger and ate a lot of the fins off the wolf eel. The picasso stayed out of his way for the most part. I loved the way he looked but I hated his appetite. He would snatch all the food immediately, take it to his domain and feast. I took him back to the store and got 45 bucks for him.

STEVE NICHOLSON - 2007-09-02
My Undulate is now 4" and well. Entertaining with a massive attitude against a 6" Picasso and at time a 9" Emperor Snapper. No permanent damage or fatalities in the last 12 months, so I'm adding a 5" Blue Trigger tomorrow! (Oh Oh?). By the way, my Tomato Clown also puts him in his place.

Anonymous - 2007-02-15
I've had an Undulated Trigger and a Volitan Lionfish in the same tank for quite some time now, and have not seen the two get into any territorial disputes or anything. However, the Trigger's reputation as being a killer is true, as I have had other fish introduced into the aquarium and they were killed shortly after by the Trigger.

I guess it's a matter as to what sorts of fish your have in the same tank as the Undulated Trigger.

Barry Asrelsky - 2006-11-25
Am getting rid of a 6"er and real fat; he's just too crazy. Pulls the food out of every fish's mouth and then after eating attacks them all. His fovorite is a clown trigger about his size. Already ate a nice passive niger trigger and he's just too nasty to keep. Thought about starting a new tank but he's too nasty. It's back to the pet shop for him.

Bill and Alyssa - 2006-03-26
I have a friend that works at Petco, and upon a visit yesterday he asked me if I wanted a free fish. That fish is a 2" Undalated Triggerfish. He told me it would help to finish cycling my new tank which still has three weeks to go. He also informed me that it would more than likely KILL my three remaining Damselfish. I asked why is he free and got the back story on how he killed another guys fish. Well I'm writing this to inform all that I took my friend up on the free fish offer, brought him home put him in my tank and have spent the last two days watching my Blue Damselfish, Yellow-Belly Damselfish, and Mystery Damselfish who was always being chased by the other two Damsels put this Trigger in his place from the get go. I have seen no signs of aggressiveness toward my Damselfish which ranging in size from the 2" Blue, and yellow-Belly to a 1/2" Mystery Damselfish. The Damsels let it be known who the bosses are especially the Blue Damsel. So far so good.. And I was given a real horror story before I decided ok I'll give the little guy a chance.