Write-Up Wednesday: Six-Line Wrasse

Today I’m rolling out a new feature on Mr. Saltwater tank.com called “Write Up Wednesday”. Each Wednesday I’ll do a write-up about a fish/coral/invertebrate/piece of equipment including my thoughts on the subject. For those of you that follow me on FaceBook, you can also find this write-up on my Facebook fan page.

Six Line Wrasse (Pseudocheilinus hexataenia)

Six line wrasses get their name from the 6 horizontal lines running the length of their body. Six lines are colorful fish as their slender bodies are made up of a background of blue with red bars. Adding to the splash of color is a green tail that includes a black dot meant to resemble an eyeball to confuse predators.

These fish do not grow very large with their maximum length being 3” (76mm) although most of the specimens I see in tanks aren’t larger than 2” (51mm). Due to their small size, they are suitable for nano tanks.

Like most wrasses, Six Lines are very agile swimmers. They can stop, hover, swim backwards and quickly accelerate away from a perceived threat. These fish are fun to watch as they will split their time between swimming in the open water column and hovering amongst the rockwork in your tank looking for pods and flatworms to eat. Six-line wrasses are sometimes recommended as a way to control flatworms (planaria) and I’m not a fan of this advice as Six-Lines have a reputation for becoming aggressive and harassing and even killing other fish. Several years ago I had a Six Line wrasse who did just that. When I first put it in my tank, he was shy and spent most the time hiding in the rock work. The fish quickly became aggressive and killed my firefish. Removing the fish took several days and I documented the removal on this Mr. Saltwater Tank TV show.

I won’t own a Six Line wrasse again. Yes they are good looking and I’m not willing to deal with one becoming aggressive. I fully realize there are Six Line wrasses out there that are good citizens and I’m not willing to put one in my tank to see if I get an exception to the rule.

If you have a planaria problem and are looking for a fish to control it, I recommend a Hoeven’s Wrasse (Halichoeres melanurus) which is also known a Melanurus Wrasse. Keep in mind there is no guarantee these fish will eat planaria as some Hoeven’s wrasses feast on the worms and some ignore them.

Bottom line: If you really have to have a Six-Line, make sure the other fish in your tank are much larger than the Six Line and are not timid.

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Comments for this article (26)

  • Sam says:

    Thanks. Been trying to find a fish to eat pods in my 30 gal. Still haven’t found a good candidate.

  • Helen says:

    Sam, I have found an orchid dotty back does this quite nicely.

  • Lyle says:

    Nice write up mark. I’ve had a few six line wrasses, they’ve all been pretty good for the most part. I think you should give them another go. And yup we just got our first big dump of snow and cold snap up here in Alberta. Keep up the awesome work you do, we enjoy it.

    Lyle from Canada Eh!!

  • Kerstin says:

    I agree – beautiful fish, but not good to have if you also want a dragonet. However, the one I had ended up terrorizing the new watchman goby I got. However, when I was trying to figure out how to catch him, he did the job himself by jumping into my overflow (I don’t have a drilled tank) – made it really easy to catch him in there. 🙂
    I returned him to the LFS, where he was eventually sold.

  • Glenn says:

    If you do have a six line wrasse do not put a royal gramma in with it, it will die. I tried it when I first got into the hobby, the six line never bothered the gramma yet the gramma was constantly running into his cave every time the wrasse came around. Even though he wasn’t outright attacked the stress created killed him. I’ve read a few articles since then talking about how these two fish don’t get along unless you have a huge tank.

  • Kevin says:

    I’ve had a Sixline wrasse for a year, it has killed at least 4 of my gobies in the last few months. Looking at getting rid of it before adding anymore.

  • Andrew says:

    Hey Mark,
    Thanks again for another informative addition from your arsenal of fish knowledge I have benefited from the past 4 years of watching every one of your broadcasts and terrible advice Tuesdays. However I have a six line wrasse that I put in my 90 gallon About 2 years ago. He is a model citizen and does not bother any of his neighbors. They all even once had a barbeque!!! I guess I am just one of the lucky six line wrasse fathers. Keep the great information coming

  • Andrew says:

    Yes I even saw him cuddling with my Royal Gramma one-on-one@ day

  • Diane says:

    I have had a six line wrasse in my 120 gallon reef for almost a year now, and it is a full 3 inches for sure and plump and happy. It is simply a stunning fish that does not bother a thing. It chased my cleaner wrasse for the first day or two I added it about 10 months ago, but has never bothered it since. I have had a watchman goby/shrimp pair for about 7 of those months, and a yellow clown goby and green clown goby for 8-9 months, and all is well. I know I am very lucky, and I love this fish! 🙂

  • Nick says:

    Could the 6-line have killed my pearlscale butterfly? The butterfly was at least 2-3x bigger but was added after the wrasse. The butterfly was eating everything and looked great.

  • Simon K. says:

    I’m really excited about your new idea about a write up every Wednesday! I think it will be much easier to share your thoughts and ideas about the saltwater tank and hobby without having to record a new Mr Saltwater tank TV show! Let us know if your willing to take requests?

    PS. A shout out to Lyle from Alberta, Canada! I’m from Alberta as well…eh 🙂

  • David says:

    Had an identical experience with a blue velvet damsel. Was responsible for the death of all fish in my tank (except curiously a Mandarin which it did not bother). It would even knock down any new corals. Impossible to catch, until I propped a large net with the handle against the side of the tank & the net against a piece of rock. Added some food in the net. At first, the damsel was suspicious and would attack the net, but by the 3rd day it would stay in the net while feeding. Simply lifted the handle and my LFS had a new resident and I was able to add fish to my tank

  • Len says:

    Good article- I’ve had the same experience…3 times.

    Also, good idea re the articles- makes it easier to pick up the ideas I want without listening to the entire tv pgm.
    Thanks- good job,

  • Darrell says:

    I have had a six-line for 2 years now along with a yellow watchman goby and a Royal Gramma, the six-line has never bothered any of these fish… I have a 65 gallon Red Sea Max.

  • Darren says:

    i never get tired of watching that 6 line capture video. i coudnt imagine catching a 6 line, i had a heck of a time getting 3 pajama cardinals out. lol

  • Mel says:

    I had a six line wrasse. I went nuts with how aggressive and very mean this little fish was. No other wrasse was safe. It killed at least 4 or more fish and limited me on other fish choices. Do not waist your money or time buying this fish for your tank.

  • Kevin Jahnke says:

    My Six line is a model citizen, I had to take it out of my main display due to a Neon Dottyback about killing it. Not a problem with the Six Line that Dottyback however is a different matter.

  • Gary Gipson says:

    I think with most aggressive fish, the larger the tank ensures a greater chance of success with compatability. Territories can be established.


  • Bryan says:

    I have exactly the same experience. My fire fish is hiding deep in my rock work and I have to target feed it. With the end of my feeder, I can tap the wrasse away. This article is my last straw! I am going to catch him no matter what it takes!!

  • Mel says:

    I would agree with you about the size of the tank; But this little devil was in a 125 and the glimpse of another wrasse it was on in an instant. It was like this little fish had radar built in. Maybe if I put him in as the last wrasse that might have helped out but I will never try a six line again just because of the aggression issues. I guess it is just like my Moorish Idol. The first one I had for 26 months and it never touched a coral or clam. The new Idol is really rough on Duncan’s and does a flavor test on any new frag entered into the tank. I guess they are individual in personally. Trying to catch one of these fish in a 125 is nuts.

  • Garry says:

    Fair warning on the Melanurus wrasse – they LOVE to eat your CUC but may not go after the flatworms. I added one to my tank because I had read that they were a good alternative to the six line. They are a beautiful fish.

    But they really enjoy crab legs. And escargot. I watched him take out $30 worth of a $50 CUC in about 3 hours. He would grab a shell with a hermit in it and shake it like like a dog does one of those rope things. Then he would throw it up against a rock over and over. Eventually the crab would fall out and he would inhale it.

    It was awesome! But consider yourself warned.

  • Larry says:

    I have had a 6 line in a 90 gallon reef tank for 3 years along with numerous dottybacks, gobies, pajama cardinals, anthias, a chiseltooth wrasse, true percula clown, 3 tangs, and a female mandarin that has been in the tank since it was new almost 4 years ago. The wrasse killed a larger male mandarin within hours after adding to the tank and has fought with numerous other fish. Once he established dominance of one section of the aquascape, he has been more content and while not exactly docile, tolerable to his tankmates. I am contemplating attempting to catch him and put in my new 180 gallon FOWLR tank and see how he likes Mr. Snowflake eel and some of the more aggressive fish in the larger tank. With 6 active aquariums housing a wide variety of fish, corals, and inverts, the 6 line is still one of the most active and entertaining creatures.

  • Joseph says:

    +1 for the hoeven’s wrasse, my favorite fish in my 110 gallon.

  • Jonathan says:

    What are your thoughts on the mystery wrasse since they are in the same genus?

  • Reef says:

    Great read!!! It’s great that you’re doing this. I was looking for some lay-man terms to understand which fish go well with others. I currently have 5.5 gallon with dwarf seahorse in. Hopefully we touch on these once in a while.

  • Milan says:

    I just caught my six line wrasse!!!!! It took 4 days with a DYI bottle trap. I’m glad he is gone. He killed a Coral Beauty Angel for sure and may have chased my CB Butterfly out of the tank and was started to work on the remaining two fish in the tank. I’ve been in the hobby for about 10 years and never had this issue with a six line. I did a happy dance like in the video when I got him. Six Line NEVER AGAIN!!!!!

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