Humbug Damsel: Prepping for the Hunt

Humbug Damselfish (Dascyllus aruanus)

Humbug Damselfish (Dascyllus aruanus)

There’s a reason I chose to spotlight Dascyllus aruanus, the humbug or three-striped damselfish, in this profile. “Caribbean” Chris and I will soon be matching wits with four representatives of this species that have laid claim to a large marine aquarium situated in one of our local coffee shops. Steve, the shop’s owner, is at wits’ end with these four humbugs, which won’t abide most new tankmates, and would like to see them captured and relocated by any means necessary, short of (or possibly including) dynamiting the tank.

Chris and I figure that between the two of us, we should have the mental prowess to outsmart these little devils, so we’re currently brainstorming the capture techniques we’d like to experiment with over the next week or so (suggestions from fellow salties are most welcome). We plan to document the process on video, so stay tuned for updates.

For the time being, though, let’s take a closer look at our future quarry:

Physical traits

humbug-damsel2D. aruanus, an Indo-Pacific species, is white overall with three vertical black bars on its sides, one extending from the leading edge of the dorsal fin through the eye and to the mouth, another at mid-body, and a third just in front of the caudal peduncle. The pelvic and dorsal fins are also black. Maximum length for this species is around 4 inches—quite a respectable size for a damsel.

I should note that a very similar-looking Western Pacific species in the same genus, D. melanurus, is also commonly called the humbug damsel (or blacktail humbug). This damsel differs from D. aruanus in that it has a fourth black band on its tail. Also, the black coloration on its dorsal fin is interrupted by white at mid-body instead of being continuous. Size-wise, this species is a bit smaller at around 3 inches.

In addition to looking very similar, these two species are much the same from the standpoint of behavior and care requirements, so everything said here regarding D. aruanus can generally be applied to D. melanurus as well.


Hobbyists often buy humbug damsels in groups when they’re still young, cute, and relatively peaceful (the damsels, not the hobbyists), but, as with so many damsel species, those adorable juveniles eventually transform into highly belligerent, territorial adults that are poorly suited to the average community aquarium. Any tankmates chosen need to be large and assertive enough to shrug off the humbug’s aggression. Also, while humbugs may share branching stony coral heads in nature, they often won’t tolerate conspecifics in the same aquarium beyond the juvenile stage.


There’s no challenge here whatsoever. D. aruanus will readily accept most standard aquarium fare. Offer this omnivore a variety of small meaty and algae-based foods, and offer several small meals per day rather than a single large one. This species will even readily accept dry flake and pellet foods, like New Life Spectrum, which Chris and I both feed to our fish and heartily endorse.

Housing and reef-friendliness

I would consider a 30-gallon tank to be minimum housing for D. aruanus, but keep in mind that a larger tank will be necessary if you plan to keep an adult of this species with suitable tankmates.

On a positive note, while D. aruanus may become belligerent toward many other fishes sharing its space, this species is completely inoffensive toward sessile invertebrates and, therefore, a safe choice for reef systems.

Photo credits: Klaus Stiefel (1,2)


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About Jeff Kurtz

Jeff Kurtz is the Co-founder/Editor of Saltwater Smarts, former Senior Consulting Editor for Tropical Fish Hobbyist Magazine, and the aquarist formerly known as “The Salt Creep.” He has been an aquarium hobbyist for over 30 years and is an avid scuba diver.


  1. Your article is spot on and I’m laughing just thinking about you upcoming adventure. I can’t wait to see the video- don’t edit it! I have a Fiji Blue Devil damsel, named Shamu, and a little yellow tail damsel, named Shorty. Shorty has survived Shamu’s harassment for 2 years. I had to move Shamu twice thinking he would not kill any more tank mates. It took me 3 days, removal of all the rock work and two people to catch him, trapping didn’t work. They are incredibly smart and fast – like a miniature killer whale
    I finally have 4 sharknose gobies who are willing to put up with his stuff and Shorty is now friends with the gobies. All is good in my tank but I had to get another tank for peaceful ornamental fish.
    With such an attitude, you would think they would be the only fish in the ocean!

    • So true, Kathy! All divers/snorkelers should be grateful that damsels aren’t as big as sharks and equipped with the same dentition. If they were, they’d be the true terrors of the deep!

      As far as our damsel-removal video goes, we’ll only edit out parts that make us look foolish and/or incompetent (might end up being a really short video).

  2. Paul Baldassano says

    You can catch those little devils by constructing a trap that is basically a clear box with a guillotine front end that closes by rubber band. In mine I have an acrylic rod that extends up to the surface and when I twist the rod, the trap door closes. It is simple. I put the thing in the tank and let the fish get used to it every day by shooting food such as brine shrimp or worms into it. When they get used to it, I wait until they are in the trap and twist the rod capturing the pest, I mean fish. I have one that is many years old and I keep it for just such an occasion.

    • Sounds like a neat apparatus, Paul. I assume it’s one of your many DIY projects?

    • Paul, Though I have no intention of ever removing Shamu, I will be following your direction for this trap. It can’t hurt to have this around just in case. Thanks for the directions.

      Jeff, Please! Leave in the foolish and incompetent parts. It’s helps us inexperienced hobbyists with our self esteem! Ha ha.

      Thanks guys for these really informative videos, I learn so much from them.

  3. Paul Baldassano says

    Jeff, my life revolves around DIY projects as I wouldn’t even know how to buy something except parts to build a DIY something. I am working on one now, with my left hand as I am typing with my right.

  4. I love to have damsels but i know how aggressive they are yet a beautiful fish same as the trigger fish not a lot between them for aggression

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