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FAQs about the Undulated Triggerfish Compatibility

Related FAQs: Balistapus 1, Balistapus 2, Undulatus Identification, Undulatus Behavior, Undulatus Selection, Undulatus Systems, Undulatus Feeding, Undulatus Systems, Undulatus Disease, Undulatus Reproduction, Triggerfishes in General, Triggerfish: Identification, Selection, Selection 2, Compatibility, Behavior, Systems, Feeding, Diseases, Triggerfish Health 2, Reproduction,

Related Articles: Triggerfish, Balistapus Species, Red Sea Triggerfishes

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Triggerfishes for  Marine Aquariums

Diversity, Selection & Care
New eBook on Amazon: Available here
New Print Book on Create Space: Available here

by Robert (Bob) Fenner

Undulated Trigger worth risk?     3/22/18
I have a 465 gallon swim tank, it has some bruisers in there. The alpha is a 10 year old foot long Sohal,
<Yikes, Mr. Ichiban>
foot long Mac Angel, 10 inch French, also some medium sized Triggers, 5 year old 6 inch Clown (never took off size wise), Red Tooth, Indian, and Huma. Are Undulate a whole different level of evil?
<Mmm; no. The Clown is about it in general... Undulated are a six-seven on their scale of being a ten. Variably territorial, but not in the same league>
Or be just another fish in a system like this?
<Something like this/that>
I had read somewhere Red Sea varieties perhaps not as nasty?
<Agreed; more easygoing from there>
One of the most beautiful fish in the hobby, but I don’t want to risk upsetting the balance.
Thanks, Kirk
<Adding anything live here is a risk; but I would not be daunted by this addition.
Please keep us informed.
Bob Fenner>

Undulate Triggerfish; comp.     7/29/17
Hello, this is Kim. I have a 125 gallon with a juv. Snowflake Eel (over a foot long, 1" diameter) and a Neon Velvet Damselfish (around 2-3"). My friend gave me a 3" Undulate Triggerfish. Would these fish get along?
<Mmm; hard to guess. Starting this small, this Balistid might; but Balistapus undulatus can be a real terror. >
I'm expecting the Damselfish and Triggerfish to fight, however, I am hoping that the Triggerfish doesn't harm the eel. A lot of macroalgae and live rocks to hopefully create territory. Thank you.
<Again, the cost of "liberty", constant vigilance. By the time your Undulated gets bigger, bitier, it may well be too late for the Damsel, and perhaps the Moray. Short answer, I would not mix it in here. Bob Fenner>
Re: Undulate Triggerfish     7/29/17

P.S. the Undulate Triggerfish is a female if that makes a difference. I don't know if it is from the Red Sea though.
<... am curious as to what makes you think you can sex this fish. Some Triggerfishes (Genus Xanthichthys) are sexually dichromatic... but not this species, when small or large. Bob Fenner>
Re: Undulate Triggerfish     7/29/17

Males have a bald patch on top of their snout, while females have stripes throughout.
<Really? Thank you for this. Will look for in specimens I encounter>
However, thanks for the answer. It's a shame how aggressive these beautiful fish are.
<Agreed... some are worse... The Clown, Queen, Titan... and they get MUCH larger>
I was really hoping that I can at least keep it with the Snowflake Eel. Damselfish, however, was probably a stupid idea. I was hoping that the damsel would be scrappy and hold on it's own. Never thought a fish would pick on an eel though.
<Many do simply to "sample" autistically... bad for the bitee. BobF>

Undulated Triggerfish and Coral Banded Shrimp?/Triggerfish Compatibility 9/9/09
Hello all,
<Hi Eric>
You probably did a double take when you read the subject line of this email: Undulated Triggerfish and Coral Banded Shrimp?
<Mmm, no, but I did do a double before I started today:)>
But that is what I have. My tank is 80 gallons and full of soft corals. My only inhabitant was intended to be an Undulated Triggerfish, but I received the Coral Banded Shrimp as a hitchhiker. I thought for sure the trigger would have eaten him, but it has been over a year and the fish shows him no interest whatsoever. The shrimp spends the most of the day hiding in the same hole but comes out to feed on occasion. The trigger can be right next to him and does not pay any attention at all. Isn't this somewhat unusual?
The trigger is about 4" and the shrimp about 2".
<Yes, very unusual. There are some triggers that are relatively safe with shrimp, but this isn't one of them.>
Thanks for any insight you might have, and thanks for all of the work providing this valuable and interesting service to the aquarist community!
<You're welcome, and thank you for sharing your experience. James (Salty Dog)>

Compatibility  7/5/09
To whom it may concern,
I have read over your site about undulate triggers. I have a 90 gallon aquarium at home. I plan to add 7 green chromis, a golden butterfly, a purple tang and an undulate triggerfish added in that order.
<Chromis viridis and Chaetodon semilarvatus would certainly get along; Zebrasoma xanthurum generally tolerates non-tang species rather well. But Balistapus undulatus? It's famous as being amongst the least tolerant fish in the trade, and while Red Sea specimens are said to be somewhat more tolerant, I think in a mere 90 US gallons you'd be pushing your luck. Have kept Balistapus undulatus in a 200-gallon tank alongside aggressive damsels, and even there, it was definitely "top dog".>
All specimens from the red sea.
Do I have enough room for my inhabitants to live a long enjoyable life?
<Excepting Balistapus undulatus, quite possibly.>
It would be a FOWLR set up. 100lbs of live rock and oversized skimmer with lots of flow in the tank.
The fish are always my main concern.
<Your tank is on the small side for semi-boisterous species like Tangs and Butterflies, and I suspect adding an aggressive trigger would lead to problems. Do review the calmer triggerfish species, or perhaps even the
more likeable filefish.>
Thanks for time.

2" Undulate and a 2" Picasso with a 7" Niger   4/1/07 Greetings WWM crew!, <Greetings.  Brandon here.>   Many thanks for your help on my previous inquiries.  I have one more for you.  I have a 110 gal tank (about 100lbs of live rock), and I've had a Niger in it for the last 6 years and he's about 7" now (I think it's a he).  I'd say he's on the peaceful side (given that it shared it's tank with a Percula clown until the clown died of old age.  But he did kill and eat a few other fish since the clown, but that was mainly my fault for pushing my luck with other clowns.  I recently added two 2" triggers (an Undulate and a Picasso).   <You are asking for it.> Right now, the undulate hides whenever Niger comes out of his caves, but Picasso is quite social with Niger and they get along fine.  But, as expected, once or twice, I've seen the undulate attack the Picasso hard (no biting) just hit him on the belly, but that's when Picasso gets too close to its home rock.   <The fish can cause internal damage by doing this.> Other times, they pass each other without an incident. Could you make any predictions about the tank over the next few years? <The Balistapus undulatus is going to grow up, and kill your other fish.  These Triggers are not social, and they have very bad attitudes.  I would move this one to a species tank and keep nothing else with it.  Further, I would not add anymore Triggers to the main display.  They need their space.>   Thanks much, <You are welcome.  Brandon.>   ND Pair of undulated triggers?  11/21/06 Hi there, <Hi Kelly, Michelle here.>  Considering that undulated triggers are sexually dichromatic, I am wondering whether it's possible to keep a male/female pair?  Everything I've read says they are best kept solo, but I have not seen this possibility addressed.  I have a 180-gal tank.  <I do not have any personal experience related to your question, I did try to find any relevant info online without much luck.  Your tank is a decent size.  It may be worth trying.  I think the best chance of success would be finding two smaller ones and introducing both fish at the same time, but it could be quite difficult to catch and remove one if there is a problem. I would definitely have a plan b and possible plan c ready to be put into motion.  Good luck!  Mich> Thanks! Kelly

Corals and Tankmates for Undulate Trigger, Porcupine Puffer and  Moray Eel   4/1/06 Hello, <Hi there, Leslie here with you this morn'in> In my 100 gal tank I have a Porcupine puffer, moray eel, and undulated trigger, question is can I put corals in and if so what type? <Unfortunately not, your Undulated Trigger will eat just about anything and everything in it's path.> I also want to add 1-2 more fish. <You will need a much bigger tank eventually if you plan on one or 2 more fish and you may need to re think the tankmate choices for your Undulated Trigger. These are very aggressive and territorial fish and should only be kept with like minded fish. Here is a quote from an article called Family Balistidae by Dave Crandall'¦.. 'Balistapus undulatus, or the undulated trigger, is a gorgeous fish; and it is one of the most predictable triggers available. B. undulatus grows to about a foot. They are found in the Indo-pacific and Red Sea at depths of 2-50m. They feed on a wide variety of benthic plant and animal organisms. These fish are highly territorial, especially females after eggs have been laid. B. undulatus is a sexually dichromic animal. The males lack orange lines on top of the snout. This fish cannot be housed in a reef aquarium. It will eat just about anything, moving or not. This fish is willing to attack and kill anything that cannot kill it. If it is to be kept with other fish, it should be in a large tank only with large, very aggressive fish. There are some reports that Red Sea undulated triggers are slightly less belligerent.' The article in it's entirety can be viewed here http://www.wetwebmedia.com/triggers2.htm> Thank You, Michael Pursley <Your most welcome. I hope this helps, Leslie>

Undulate Triggerfish...Hope This Tank Is Huge! - 02/06/2006 Hi <Hi there John.> I am thinking of buying an Undulate Triggerfish. I read they are quite aggressive. <Yep!> Do you think it will be fine with the following fish or should I leave it alone? 3 Clowns 1 Lipstick Tang 1 Sohal Tang 1 Regal Tang 1 Sailfin Tang 1 Purple Tang 1 Picasso Trigger 1 Niger Trigger 1 Clown Trigger 1 Copperband Butterfly <If this system isn't at least a couple/few hundred gallons, you're likely to have trouble already! I'd not add this fish.> Thanks John <Sure. - Josh>

Trigger & buffer question  8/30/05 Hi, I have experienced 2 different times where a trigger of 4 and 5 inches in length started out fine in my 100 gallon tank and after a couple of weeks they stopped eating, then got a bloated stomach, started breathing hard, then 3 days later would die. There is a big undulate (almost 7") in the tank but it never bit them, she would let them know she was there, but did not chase them. When a trigger is stressed, is the stomach thing I saw common? It just looked like they had a full stomach. <Is very likely "just" stress... like you having a "friendly" tiger in your house, no way to get out> Second, I have been experimenting with baking soda and borax. I have been reading all I can find, and with my own experimentation have found that 2 parts baking soda and 1 part borax produces 8.2 Ph. Have you guys heard of this before? <Oh yes> I have been using it for about 3 weeks now without trouble (besides the noted triggers) from a niger, louti grouper, lionfish, undulate, miniata, coris wrasse, humu. (they are in various tanks!!!!) Thanks, Dan. <These are the principal ingredients in most "pH buffering" commercial products. Bob Fenner> Undulated Trigger... trouble Bob, << JasonC here, standing in for Bob. >> Nice Site. You seem to be very well informed on Triggers. I read the FAQ and did not see any info on Undulated Triggers. Probably because most people are smart enough to stay away from the mean bastards. << I am a trigger fan myself and this is how I was initially drawn to WWM. Bob is not far away and will appreciate your kind words. You are quite correct about the undulated triggers. >> Here is my problem. I have a 4 1/2" Betta, 3 1/2" dogface puffer, 10" snowflake eel, and I just added a 4" UNDULATED trigger. I know the rule when adding a Trigger. Always make sure it is the smallest of the fish in the aquarium. I thought it was close enough. The Betta gets nipped at once in awhile and is segregated to a corner most of the time. The puffer has no fear and will not give up territory. The result is it is nipped at much more. He refuses to use is defense mechanism and allows himself to get nipped. I was hoping one "puff" might make them more compatible. The puffer is very healthy and vibrant but the marks he receives are beginning to worry me. The trigger has only been in the tank for about 2 weeks. Its a 60 gallon tank. << you're right again, that is a problem >> Is there any chance that the trigger will become less aggressive as he gets more comfortable? I will be very sad if he makes my puffer unhappy or even worse kills him. << it's a coin toss that the trigger will either get better, or get worse, and if I was a betting man, I'd take worse. Likewise, it would be unfortunate for this newcomer to spoil an otherwise peaceful tank. >> Although I want to avoid this, should I trade him in for 2 SMALL triggers (2-3 inches)? I would want a clown and UNDULATED. Am I just a glutton for punishment or would the extremely small size make them ok? << don't avoid it. No to the two small triggers of those types - two baby attack dogs. Perhaps you are a glutton for punishment. You could maybe try a small Huma trigger, they are often on the lighter side of the temperament scale. >> On a less important but curious note. I bought two blue damsels, two Dottybacks, and 2 black fish that are similar to dottys. The trigger fed on the both dottys then eventually the other two blackfish in order. The blue damsels have been left uneaten for 2 weeks. Any special defense or just dumb luck? Sorry for the length of this mail. << faster combined with dumb luck. Give the trigger time and their luck will run out. >> Thanks in advance, << you are quite welcome >> Bob

Same Trigger, Same Trouble Bob, I wrote about the Undulated trigger problem. My puffer is a PORCUPINE puffer NOT and DOGFACE PUFFER. << JasonC again... same advice applies. >> Regards, Bob << Cheers, J -- >>

Trigger Tribulations Here's my question...I found a 3-4 inch Undulated trigger, that is very shy. <He won't be for long!> Every time I see him he runs and hides.  Now here's the problem, I have sea anemones (1 Condylactis). Will it eat or pick at it? <Almost certainly> I'm also thinking about picking up some clowns and a carpet anemone. <Not in the same tank, please!> Do you think this trigger will have a problem in my tank?  It's a 55gal w/ a med porcupine puffer, large Tang, Blue devil damsel, Atlantic Starfish, and a snail. The puffer has a good temperament except for small fish. Any ideas? Erik B. <Well, Eric- I hate to be the bearer of bad news, but there are a few things wrong with this picture. First, the Undulated Trigger has a well-deserved reputation for being one of the most aggressive, pugnacious fish kept in aquariums! It's not a matter of if it will be a problem  with other fish, but WHEN! Really should have a tank of his own. A LARGE tank- this guy can reach a foot in length. Your 55 is too crowded! The puffer is an awesome, adorable fish, but he gets HUGE, and needs a big tank with vigorous filtration. Just about any tang will outgrow a 55 gal. My purpose in pointing these problems out to you is not to "scold' you, but to give you an idea as to what you're getting into with a fish like this! I love your enthusiasm and interest, but please take some time to study future fish purchases before you act. A good book, like Bob's CMA, or Scott Michael's "Marine Fishes", will go a long way towards helping you make good decisions. Please consider swapping these fish with someone who has the facilities to keep them for their full life spans, and at their adult sizes, or be prepared to buy a very large tank. You will be a successful aquarist, but you need to be more aware of the long-term implications of purchasing large fishes, and the responsibility that goes with them. Keep reading, learning! You'll be fine! Scott F.>

Don't Sweat The Aiptasia- He's "Trigger Happy"! Hello -- WWM Crew <Hey there- Scott F. with you today...Had server problems last night- I don't think that my reply got to you intact...Got me on the laptop in bed this AM (scary imagery, I know-but a great way to do WWM work!) trying again!> I have a 125 gallon tank with a Undulated Trigger and a Huma Huma both about 4.5 inches. I am aware of the potential of both Triggers particularly the Undulated.  My intentions are to get a larger tank soon. <Very good intentions, indeed! These guys will get quite large, and quite boisterous down the line. The 120 should be okay for a while, though> However the two get along fine now an occasional snap by the Undulated during feeding but they typically swim right next to each other without confrontation.  The tank is loaded with coralline encrusted live rock which provides plenty of hiding places.  I have two questions the first is how do you tell a Red Sea Undulated from the more nasty/aggressive I guess Indo Pacific?? variety/subspecies? <As far as I know-this species does not have any instinct geographic color variations. I did check a number of non-aquarium resources for you, and was unable to find any information in regard to this.> I understand Undulated Triggers are sexually dichromic --- I have a female with orange lines down to her mouth. <Yep- the sexual color variation is a fact. And I concur- you seem to have a female, as males do lose the orange lines around the snout as they mature> Reason I am asking is that I read the Red Sea can possibly become a long time tank mate with other predatory types --- but the other subspecies? Makes survival of a tankmate highly unlikely --- is this accurate? <To be quite honest with you, in my experience with this fish, as well as the experience of a few friends who currently maintain them- they are just tough customers, regardless of where they hail from. They tend to become more feisty as they mature. However, triggers are notorious for being "non-conformists" to our behavioral expectations of them in captivity! I have seen 10 inch Clown Triggers that seemed very "tame", and small Crosshatch Triggers (reputed to be more "gentle") just beat the @#$% over anything that they were placed with!> The second question is I have live rock with what appears to be anemones growing on them.  The anemones?? are small and not very colorful ---kind of a caramel brown color. Does this description sound familiar enough for you to guess if they are anemones? <Yep- all too familiar, actually! Sounds a lot to me like the famous (or infamous, depending upon how you look at them) Aiptasia anemones! They tend to come in on live rock, and proliferate with remarkable speed in tanks with higher nutrient levels or bioloads (such as...a trigger tank!). Reefers freak out when they see Aiptasia because they tend to overrun other (desirable) sessile inverts and corals. However, in a FOWLR tank like yours, I would not be too concerned, other than to see if they are indicative of sub-par water conditions (probably not, though). The anemones(?) are multiplying and the Triggers don't seem to bother them at all --- My question is can Anemones and Triggers co-exist for long or will the triggers likely damage the Anemones?? <Well, I wouldn't go out an by that tank-raised Bubble Tip Anemone just yet! My personal theorem on anemones and triggers is that the possibility of the anemone becoming a chew toy for the trigger is directly proportionate to the value and attractiveness of the anemone! Just not a great idea, IMO. I wouldn' worry about the Aiptasia, at this point, however...Sounds like your pals aren't too interested in them- yet...Aiptasia are interesting animals in their own right- very efficient at what they do best...eating. In fact, Anthony (Calfo) has even gone so far as to suggest that they could be harnessed in a special raceway as a natural biological filtration supplement! They are that good at eating!> Thanks in advance for your response <My pleasure! Thanks for stopping by! Regards, Scott F>

Triggerfishes for  Marine Aquariums

Diversity, Selection & Care
New eBook on Amazon: Available here
New Print Book on Create Space: Available here

by Robert (Bob) Fenner

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