Please visit our Sponsors
FAQs about Flatworm Predatory Control

Related Articles: Pest Flatworm Control by Anthony Calfo, Flatworms (incl. Planaria), Worms, Featherduster Worms

Related FAQs: Flatworm Control, Chemical Control, Flatworms/Planaria 1, Flatworms 2, Flatworms 3, & FAQs on: Flatworm Identification, Flatworm Behavior, Flatworm Compatibility, Flatworm Selection, Flatworm Systems, Flatworm Feeding, Flatworm Disease, Flatworm Reproduction, & Fish Worms DiseasesWorm Identification, Worms, Fire/Bristleworms

Possibly: Nudibranchs; Chelidonura varians,  Shrimp: Lysmata spp. Wrasses: Anampses, Halichoeres chrysus, Lined/Pseudocheilinus, Pseudochromids, Wetmorella sp., Macropharyngodon, Novaculichthys,  Callionymids/Mandarins,

AEFW... chem., bio. controls    1/22/14
What's the best course for action for eradicating AEFW?
<Mmm, there are a few approaches... mostly 'cides; chemical controls>

I've searched the site and come up with the below as possible in tank treatments:
1) Levamisole dosed at 28g per gallon, repeated each week for 4-5 weeks along with a 50% water change.
2) Salifert FW Exit dosed at 4 drops per gallon, repeated each week for 4-5 weeks along with a 50% water change.
Are there other more effective in tank treatments or dips?
<Not IME; I'd go w/ #2>
Thanks for your time.
<Welcome. Bob Fenner>
Re: AEFW   1/22/14

What's your opinion of fluke tabs @ 1 tab per gallon?
<Mmm; can work. Again, if poisoning the system, I'd go w/ Salifert... Have you tried, considered bio-controls?>
Are any dips effective specifically: CoralRx, Revive, Iodine, RPS All Out, or Bayer?
<Have no direct, first-hand experience w/ any of these... Anecdotal accounts are mixed for all. BobF>
Re: AEFW   1/22/14

I have two Halichoeres Wrasses (Yellow Coris and Christmas), are there other bio-controls I could try?
<Mmm, genus Halichoeres wrasses don't do much for AEFW... generally will only eat if blasted off and they're hungry. My fave hands-down choices are members of the genus Pseudocheilinus; mystery, six-line... B>
Re: AEFW   1/23/14

A side note, I'm cycling/upgrading a new tank so I'm prepared to move all unaffected livestock to the new tank, turn the current tank into a QT and do whatever is necessary to remove these pests before relocating the corals to the new tank (if possible).
<Best to treat all; the system... B>

Red/ brown flatworm problem    2/11/13
Hi -
I recently developed a red/ brown flatworm problem in my 110 reef tank. I have several peaceful fish including a Linespot Flasher Wrasse & I just added a Six Line Wrasse to help control the flatworms. They seem to get along fine. I was thinking of adding a Green Wrasse (Halichoeres Chioropterus)
<... mis-spelled>
 to help with the flatworm problem. From what I read, the Green Wrasse is peaceful but I am getting mixed message on whether they are reef safe. Can you clarify?
<Is amongst the most "reef safe" of fishes>
 Also, will I have a problem with
compatibility with having these 3 wrasse in the same tank? -Ron
<The Sixline may chase, harass the others, but this volume and shape tank should accommodate all. Bob Fenner>

Check this out.... species of Damsel that eats FWs??? 4/16/09
Howdy Bob, Adrian from AZ here.....
So I was in a LFS the other day getting a ballast (never fun) and mentioned to the SW guy named Andy (Pets Inc. in Tempe AZ) that I had a small infestation of Flatworms for about 6 months now. He pointed me to this tank with 2 damsels in it. Says that these blue "Damsels" will eat them, they are not the regular blue damsels. SURE I said, but decided to take him home and give it a shot. Well its been about a month now and he gets along GREAT with my female Picasso clown (who is a real you know what) and there is no sign whatsoever of Flatworms. CRAZY. So I thought I would send this to you, for your posting pleasure on WWM and maybe you can ID the damsel, maybe just a common blue damsel? Anyway Enjoy and will talk soon!!!
Fish and Reef Aquarium Group
<Thanks much for this Adrian. Will post, share. BobF>

Check this out.... species of Damsel that eats FWs??? 4/16/09
Hi there Bob,
I think that pretty little flatworm eating fish just might be a Springer's Damsel/Blue Sapphire Damsel, aka Chrysiptera springeri:
Take care,
<I do agree... and will attach your ID. BobF>

Compatibility and natural predators, Flatworms   2/4/07 Hi Crew, <Cin> I just recently talked my LFS out of an older tank in their store. I wanted to upgrade my 55-gallon, seahorse reef to a larger tank. I also did not want to recycle a new tank setup with my livestock living in a holding tank. I purchased a 125-Gallon with overflow systems predrilled and a 30-gallon sump with built in refugium. Metal halides and actinics for lighting and added led moonlights for seahorses dusk to dawn effects. I talked them in to the sand, water, and all filtration, as well as some fun frags; found in the bottom of the tank. I used the sand from the new tank, as well as the sand from my current tank to build a DLSB. I did a 15-20 second hypersaline dip on all rock transferred, as well as iodine dipped most of the corals, I only did this to rid a few bristles, I was aware of, and the fact that some of my amphipods are getting much too large for food. I also had suspected them of munching on softies. Inhabitants are as follows: 1 Lobo, and 1 Trach. Brian, <As in "the life of?"> Leather Corals, both Cabbage and trees, 2 Echinos, Gorgonias, small polyp colonies, mushrooms, and a few types of macroalgae. My tank is 24 " deep, 28" tall and 60" long. My livestock is minimum with a large cleaning crew of 12+ Peppermint shrimp, 18+ Astrea snails, 12+ Cerith snails, more thank <Welcome> 2 dozen Nassarius snails, 4 medium sized tank raised Erectus as well as 2 small Barbouris, six seahorses in all, and one Jawfish Goby. I have a 4-inch sand bed with a small amount of aragonite for assistance with calcium and ph, more so for looks, to freshen the older sandbed. I currently have a nice mix of approx. 70 lbs. of live rock. Nitrites 0, Nitrates 0, (thanks to Bob) <Heeee!> Ammonia 0, pH 8.2-8.3, Salinity 1.023-1.024. Temp 75. Now to the real question. I must have gotten the flatworms free with the new tank. <Freeeee!> Unfortunately they have no predators. I have also decided this would be the last batch of seahorse babies, I intend to attempt for a while. After hours each night on your site I have ruled out nearly every natural predator I chose. <There are none guarantied> I need a fish in this tank! Qualifications: must be passive, must eat flatworms, can't be toxic or aggressive eaters. No coral or fin nippers. Don't want this thing to make meals out of my macroalgae, and to top it all off hearty would be a plus. It also must get along with Jawfish. I know mandarins a hard to keep, and understand they shouldn't be housed with Goby, they also will compete with seahorses for food. Damsels are a seahorse's nightmare, everything else I studied would have my corals for dinner. I thought possibly about a Batfish being the perfect companion for the current occupants, but wasn't sure how appetizing my horses may look to him in 6 months. <Would be/get way too large...> He also seems a very expensive attempt at failure, and I am not sure if he would help me at all in the flatworm department. I have torn this site apart for two weeks now looking for a sand sifting, flatworm eating, non-aggressive, non-stinging tankmate. I have no problem adding a few inhabitants if need be. I eventually would like to house approx. 10 horses in here. I don't care if I need Nudibranchs and fish or cleaner crabs and small starfish (any suggestions). As long as something will eat flatworms, smaller fish, amphipods and not corals. If I have to choose something toxic, or inking, what are the consequences to the invertebrate and corals? <Could be dire> Please help. Sorry this took so long but I wanted to explain everything. I have racked my brain and worn holes in your site. Which by the way is quite awesome after spending as much time on this as I have. Thanks for all you do! Cindy <I'd leave the flatties be... likely they'll cycle out, go on their own in time... You can make a bit of sport of them... siphoning out a few with water changes... This is what I'd do. BobF>

Fishy Flatworm Predators? -- 01/22/07 Hello there, <<Howdy>> I had a really bad flatworm infestation in my old tank which I had tore down when we moved last year, to the point that they virtually covered all the live rocks' surface and lots more on the sand and glass. <<Mmm, a generally overrated pest in my opinion...will usually 'cycle out' of a system or reduce to the point where they are insignificant...though admittedly they can multiply to plague proportions under 'ideal' conditions>> To complicate the problem the tank is a soft corals and mushrooms dominated tank and increasing flow isn't much of an option. <<I disagree, even 'softies' benefit from a good deal of 'diffuse' flow>> I have tried a six-line wrasse and a green spotted mandarin and they didn't seem to make a dent to the flatworm population, if at all, but decimated my copepod and amphipod population. <<Agreed...'shots in the dark' as far as finding a reliable biological control>> They sure know what taste better. <<Ha!  Indeed they do>> Eventually when I broke down the tank when we moved house I treated all live rocks and corals with Flatworm Exit, which I find ineffective at lower dose (up to 2 time recommended dosage) and effective but devastating to some invertebrates especially the echinoderms at higher dose (up to 10 time recommended dosage). <<Yes, and a whole lot more than the echinoderms that you don't/didn't see...the inherent dangers/pitfalls of 'nuking' your tank>> Right now I am in the midst of stocking a 120G mushrooms and soft corals tank.  I don't have any flatworms that I can see now, but I wish to have something that will eat them just in case I have them.  Personally I like longnose Hawkfish or a psychedelic mandarin for the look, which seems to be reported to eat flatworms. <<I don't consider either of these to be reliable for this purpose...and the mandarin less-so than the Hawkfish, aside from its inappropriateness for a new/immature system>> But the six-line wrasse and the green spotted mandarin seem to have a better reputation in the utility aspect, though I have unsuccessfully tried them. <<Exactly...>> I'm also looking at yellow canary wrasse which seems to be less aggressive alternative to six line wrasse. <<Halichoeres chrysus?  Wonderful fish for reef systems!  Though this species too is no guarantee of a flatworm predator it is wholly worth adding in my opinion for its color/activity/peaceable nature>> Now I understand that there is no absolute chance that a species of fish will eat flatworms. <<Much agreed>> In your experience or opinion, is there a particular species of fish that has the highest chance of eating flatworms? <<The smaller wrasse species are likely your best option...and a 'mix' of species at that.  Though this can be problematic if species are not chosen carefully for compatibility or introduced in the correct order.  I would stay away from the mandarin species altogether.  These are the least reliable in my experience...as well as likely to merely starve to death in the long term from inadequate natural food supplies>> Or it doesn't really matter because it is a luck thing anyway and I should get the fish that I like most? <<This is what I would do...as well as utilizing quarantine/dips to try to prevent introduction of this pest organism in the first place>> Please don't hesitate to give me your personal recommendation, WWM will not be held accountable if the fish I end up with doesn't eat any flatworms. :-p <<No worries there mate [grin]...we do say what we think/give our honest opinions>> By the way, I do have ornamental shrimps.  What is the risk like for the longnose Hawkfish or the wrasses to eat them? <<Fairly high with the longnose, especially if any small/are introduced after it is.  The H. chrysus is much safer here in my opinion...as are most of the smaller wrasses>> Thank you for reading. Cheerios, Wid <<A pleasure to share.  EricR>>

Re: Fishy Flatworm Predators? - 01/23/07 Hi Eric, <<Hey there Wid!>> Thanks for the prompt and detailed response. <<Most welcome>> We really appreciate for the time and effort that you guys put in. <<Is a pleasure to assist>> I guess the smaller wrasse is the way to go for me. <<Cool>> Yep I meant Halichoeres chrysus (did I spell that right?), <<Nearly [grin]...is Halichoeres chrysus>> they are regularly available here locally, and I'll most probably get one of them, or some other more comparable species (peaceful and small) if available. <<Very good...there are several species of Halichoeres that make excellent reef specimens>> Thanks again. Cheers, Wid <<Be chatting, EricR>>

Pest control-flatworms and the like Hi, I have a 72 gal saltwater FOWLR set up.  It is 6 months old and doing good, except for a few things.  One is I had an unbelievable abundance of amphipods a few months ago.  It looked like the entire sand bed and the live rock was constantly moving, their were so many.  And then came the flatworms.  They are the little white ones, round at the head and then taper back into two little "legs".  These things multiplied and grew and now I have hundreds of flatworms and no amphipods.  You could see the worms eating the pods, so I'm sure they definitely had something to do with it.  The only fish I have are one ocellaris clown and a longhorn cow.  And yes, I will be getting a bigger tank when the cow grows up, but right now, he's only three inches long. My concern is, I had planned on getting a good amount of pods, to hopefully be able to add a mandarin to the tank.  I have been reading that mandarin's have no interest in flatworms. << I don't agree with that.  In fact I have a hard time advising anyone to buy a mandarin, but sometimes do advise this when they are battling flatworms (Planaria).  However, there are better fish to control flatworms, which I'll get to. >> Too bad.  I am interested right now though, in finding a "peaceful" predator to naturally eradicate these alien creatures from my tank.  Any ideas would help.  <<  Okay, I recommend a wrasse.  Some people find good luck with six line wrasse, or a dragon wrasse. I haven't personally tried either of those, but did have success in my tank using a Puddingwife wrasse. Another option (as hard as this is to believe) is that many people have reported success using the common yellow tailed blue damsel. >> I have also a question concerning those little "internal refugiums" that can be suctioned to the inside of your tank.  Would one of those be suitable to help sustain an amphipod reserve for a future mandarin? << Absolutely.  Any type of refugium would be of help.  I of course would recommend a large sump type of refugium, but any refugium would help. >>  Also, I have recently noticed tiny little worms crawling up the side of my tank.  They are about an inch long and so thin they look like a scratch in the tank until they start moving.   They also tend to curl up their tails and in defense, will curl into a little ball.  I had a bristleworm when I first got this tank, but that was about 6 inches long and very fat.  Do you have any ideas what these may be?  Are they harmful, and do they have any natural predators as well?  << I don't know what they are, but I certainly wouldn't worry about them.  If something eats them, fine, if not, fine.  I wouldn't look for a predator because as your tank matures everything will take care of itself. >> Hopefully you can help.  Thanks again for the info.  <<  Adam Blundell  >>

Acro Flatworms, the dilemma  - 03/09/2006 Guys, <And some ladies...> Quick question, thinking of the best way to eradicate the dreaded scourge of sps (I know I should have QT'd), now I have these monsters, of course I am blowing the Acros and destroying eggs, but as far as fish go, I read Tamarin, yellow wrasses and possum wrasses work. <Sometimes> Im looking for the most aggressive fish I can get to kill these things, any chance triggers might work too? <... won't likely stop at the Platyhelminths...> Any other fish you might recommend? My tanks is sps only so these blasted things are having a field day! Thanks <See WWM re... your input is archived. Bob Fenner>

Flatworms Hello Bob, <Anthony Calfo in your service> I have a question concerning flatworms. And the more I read the more confused I get. <hmmm...do read this piece of mine (http://www.wetwebmedia.com/pestflatwrmanthony.htm) and the many FAQs on the subject ( http://www.wetwebmedia.com/flatwormfaqs.htm)> First off I have set up a twenty gallon tank in the office where I work. Have 1 scarlet hermit and 4 snails. Added a false perc clown, who now has developed a fuzzy growth on his left gill. I believe this to be Lymphocystis.  <yes. may very well be. There are not many "fuzzies" in marine fishes...true fungus being very uncommon and Lympho being rather common...look here as well: http://www.wetwebmedia.com/lymphfaqs.htm> The clown is very active and does not show signs of distress. I now know from your site that this is not as bad as I first thought. And will eventually clear up. <agreed> Now on to the flatworm problem. I have two kinds of flatworms. Please correct me if I am wrong. One is a white kind that actually looks like a tooth, I have read that these eat copepods and such. And will not get to plague proportions.  <yep... and rather a good sign that you have a healthy copepod population to sustain them> I also have green to greenish brown with a orange or reddish spot in-between the forked end. These seem to be all over everything. I was considering getting a fish to help control this problem. Can you recommend one? I was looking towards a six lined wrasse, as they stay small and are hardy, and colorful. Will this work.  <yes.. a good change and such small wrasses are some of the most effective and hardiest choices> Or how about a scooter blenny?  <not recommending any dragonets/blennies as a first choice... not hardy or effective enough> I am not to concerned about the pod population, as I know it may be decimated by the wrasse,  <not so much...> but I was told the scooter blenny, well actually mandarin, would eat the flatworms and some algae but not harm the pods as much. <that is very incorrect... pods are most all/only what they eat... the reason why they are so difficult in aquaria that have difficulty sustaining copepods populations for years in continuum> Thanks in advance Paul <best regards, Anthony>

Natural Flatworm Eradication Technique....Maybe Bob, et al., <Hi Chuck PF here this AM, not sure if I qualify as an et or an al> My 300 gallon tank was filled with these ugly buggers...until I added a refugium with low flow rate. ALL of the flatworms have since migrated to the refugium...not a single one in the main tank. Perhaps this is a clue as to how to get rid of them ? The display tank has been flatworm free for almost 1.5 years, and the refugium is loaded with them. <Wow! Very cool.>  I really do not care that they are in the refugium since some sources I have read suggest that they could actually be beneficial to the overall health of the system, albeit their unsightly appearance. Maybe I stumbled across a technique that could be used to eradicate these pests ? <Sounds that way to me.> This is how it should work: 1. Either set up a permanent low-flow refugium OR set up a temporary low flow tank that is plumbed into your system. 2. Increase the flow rate and/or water motion in your main tank with powerheads, closed loop pumps etc. 3. Then wait..... 4. Watch all of these buggers migrate to the low flow tank. 5. Once you got em in the temporary tank, disconnect it and flush em or just leave them alone in the case of a permanent low flow refugium. Do you think my situation is just a fluke, or something really exciting that I stumbled on? <See below> If someone could duplicate this, maybe we could confirm this technique, n'est pas ? <Sounds like a plan to me, if multiple users repeat your results successfully, then you may well be up for Saltwater Sainthood. :) > Best Regards, Chuck <Thanks for sharing Chuck, hopefully your technique will work for others. Have a good one, PF>

Acoel flatworm eater, The New Book 5/30/03 Hey at WetWeb, <Howdy!> I spoke with Anthony a couple months back and ordered his and Bob Fenner's new book, and I'm curious as to when I will receive it.  I assume it will be soon??? <indeed, my friend. We just got word from the printer that they estimate a June 13th release. It then needs to be shipped to Cali (less than a week) and then Bob and I need to fly/meet together to sign the pre-orders. We'll get them out promptly!> Also, I was perusing your site and noted that when people asked about ways to eliminate Planaria from their systems, the Six-Lined Wrasse was not mentioned.  This is a fish that will wipe out a flatworm infestation in short order.   <unfortunately not all do to exclusion. Many aquarists have this popular fish but they will not control Acoel flatworms for them> Perhaps you'd like to include that info in future responses.  They are wonderful little fishes to boot! <agreed... will be sure to archive this response> Look forward to a response on the ETA of the new book. Thanks, Peggy Nelson <Thank you for sharing, my friend. with kind regards, Anthony>

Flatworms What fish or any type of reef animal eats flatworms? Is there an easy way to get rid of flatworms? <All your questions can be answered by reading the following on our webpage: http://www.wetwebmedia.com/flatworms.htm http://www.wetwebmedia.com/pestflatwrmanthony.htm http://www.wetwebmedia.com/flatwormfaqs.htm> Thanks <You are welcome. -Steven Pro>

Flatworm Infestation/Biological Controls - 05/02/06 Hello, <<Howdy!>> In my 40 gallon reef tank I have a large population of small orange things smaller than the size of a pencil eraser.  They are flat, have bilateral symmetry and no (or not noticeable) eyes, if that helps. <<Sounds like Acoel flatworms>> They reproduce very quickly as well. <<Under optimum conditions, yes>> They'll cover up half of a wall in the aquarium, I'll remove them and in two days it's covered again. <<Mmm, I usually consider these worms to be mostly an overrated pest to be controlled by limiting excess nutrients/detritus in your system...though when reproducing in plague proportions they can damage sessile invertebrates by shading/smothering>> Would something like a Blue Velvet Nudibranch or a Six Line Wrasse (both of which I'm told eat flatworms) help? <<The Nudibranch (Chelidonura varians) is the surer bet, but will starve to death once the flatworms are gone.  If you go this route perhaps you can loan/sell the flatworm to other like infested aquarists in your area...or make a deal to return it to the store to be utilized elsewhere.  If you decide to try a wrasse, though no sure thing either, I think one from the genus Halichoeres is a better pick than the Six Line>> All parameters are in check and salt is fine.  The other inhabitants are two clowns, a lawnmower blenny, a small tang (not big enough to go in the bigger tank yet.<<?!>>) several snails, two cleaner shrimp, random zoos, normal leather coral and Cabbage Leather Coral, Crocea clam, torch coral, red-tipped bulb anemone, and random mushrooms and feather dusters.  None of the inverts have been bothered/attacked by the orange worm things though. <<Typical>> Any help would be appreciated. <<Failing a biological control, manual extraction along with judicious feeding, detritus removal, and increased water flow/circulation can usually overcome this common pest>> Brian <<Regards, EricR>>
Flatworm Infestation/Biological Controls II - 05/03/06
Hello again, <<Hi Brian>> I did a Google image search for Acoel flatworms and it looks exactly like what I have.  I also noticed the Blue Velvet Nudibranch recommended so that's my plan. Thanks! Brian <<Do think beyond the flatworms and have a plan for the Nudi after they're gone.  Regards, EricR>>

Flatworm Predators/Controls - 04/18/06 I've been running my tank for about 4 months now with great success. <<Ok>> I have an 180gal. with two refugiums: the first is a 45 gal. Chaetomorpha refugium without sand, I also have a dark (blue light) live rock with 5" of sand.  Total system water with sump is around 300 gal.. <<Very good>> I'm writing to you because I seem to have a growing plague of what I believe are Planaria flatworms. <<Common/present in many folks systems...and a bit of an overrated pest in my opinion.  Harmless in most instances unless in plague proportions where they can completely cover corals, starving them of light/water circulation.  Reducing/removing dissolved organics with judicious feeding and aggressive skimming can usually control their numbers>> They are prevalent in the Alga refugium and now more and more in the main tank.  Some of the advice that I have gathered so far are: more circulation, manual extraction, and a natural predator such as the Velvet slug. <<The "slug" is a Nudibranch (Chelidonura varians).  They are reported to feed on Acoel flatworms, though I believe they are hard to find...and I've read there is a similar looking imposter that is often sold as the Velvet Nudibranch that DOES NOT eat flatworms>> My fish and Shrimp load is: Sailfin Tang, Lawnmower Blenny, Mandarin dragonet, Diamond Watchman Goby, Blue Tang, 2-peppermint shrimp, Coral Banded Shrimp, Blood red Fire Shrimp. I have a few corals and a clam also.  I'm interested in adding the velvet Slug for these worms or might you know of a natural predator in the Wrasses family? or others? What about the Six Line Wrasse or Carpenter's wrasse? <<None of the so called "flatworm predators" are completely reliable.  In my opinion the percentage is greater that they will completely ignore the worms.  But, I have had limited successes with wrasses of the genus Halichoeres...particularly Halichoeres chrysus.  You could give one of these a try, but I believe manual extraction and controlling water chemistry are your best bets>> Tanks a lot for the advice, Stephan Gaudreau. <<Hope you find it helpful.  Regards, EricR>>

Red flat worms? Hi Bob I am from Warsaw in Poland. I have a 125gal tank with live rock, soft and hard corals, 7 fish and 4 shrimps. Two weeks ago I saw plenty of flat worms especially on my three Sinularia and on the glass. Small, flat, brown creatures approx. 1-3mm. On the one of my Sinularia there is something like a light brown cobweb, the other is covered something like a light brown powder. I am siphoning it off, but without effect. I have heard that Mandarinfish eat these worms. I was also thinking about using Marin Oomed or Gold Oomed (Tetra). What suggestions do you have? Thanks. Krzysztof Tryc >> Don't go the chemical route (just yet)... do try a mandarin (here goes my plug again for the related, same family, Callionymidae, Synchiropus morrisoni... and if that fish doesn't eat your particular type of flatworm... we'll try the next one in line... a wrasse species of the genus Pseudocheilinus. I wouldn't worry (too much) about the cobweb and dust appearance on your soft corals at this point... Bob Fenner

Red worms all over Dear Bob, I am having a huge problem with red acoelomate flatworms. They have taken over my beautiful 25 gallon reef, and I suspect that their high populations are the cause of my horrific algae problems (from what I understand, the accumulate toxins and release them when they die). My water parameters are good (0ppm Nitrate and phosphate). I plan on tearing down the tank (unless I can get rid of them otherwise). I would like to reuse the rock and aragonite, so can you please offer any advice on how to rid them from the rock permanently? Thanks. Avery >> There are a few approaches... the biological (roulette) is the best to start with. What potential predators have you tried thus far? Some crabs, fishes eat some of these worms... How about a Callionymid to start? That is, a type of "mandarin"... my best one to begin... probably a Synchiropus morrisoni... then we'll raise the bar if this doesn't do the trick... what shrimps have you had? Did anything eat any of them or even look interested? This is an important clue as to palatability. Bob Fenner

Flatworms "Planaria" My 135 gal reef tank which has been set up for about 1 year recently developed an infestation of Planaria. There have been no new additions for the last four months. The corals are still in excellent health and are exhibiting signs of growth. They include Green Hammers , Red and Green Open Brains, 3 Elegance, Bubble, 2 Varieties of Hydnophora, Torch Coral, assorted mushrooms, A Cynarina lacramalysis, (meat, modern cats eye), and an unidentified leather possibly a devil's finger. I've even tried a mandarin goby and a six line wrasse and still these pests are present. I really have not seen either fish eat any of these flat worms. Sprung & Delbeek in Vol 2 recommend a variety of Nudibranch, C. varians. The fish population is small 2 perculas, 2 green Chromis, 3 Chinese zebra gobies, Randall's goby. Any help would be greatly appreciated. Greg >> I know what you mean... and it's tough to get rid of these flatworm plagues... even if the animals don't appear to be causing trouble. Other than selecting vacuuming them out, keeping an eye out for the elusive specific Nudibranch predator, I'd try another, in this case, larger species of "lined" wrasse (genus Pseudocheilinus), either an Eight Line or an Evan's or Disappearing Wrasse... Let's keep our fingers crossed that these labrids find your species of flatworm tasty. Bob Fenner

Flat worms! A friend of mine asked me to email you. His 180 reef has the dreaded flat worm problem. His gobies seem to do a good job of keeping them off the open areas of sand, but around the edges and up the sides look horrible. Any thoughts on how to "stem the tide?" And how do we prevent the outbreak from occurring in the first place? Thanks! By the way, he's got a bunch of live rock, lots of corals, Kole tang, 2 gobies, a mandarin, blue tang, etc. He doesn't want me to tell you, but he's my LFS guy! He's now asking me for advice! >> <Hmm, you might want to look into the SeaSlug Forum on the Net, and try one or more of the celebrated species... Other Pseudocheilinus Wrasse Species... are worth a go as well... the list can go on from here. Bob Fenner

Flatworm eaters Hi Bob, <Lorenzo Gonzalez here, Bob's in Asia somewhere for a while...> I have recently had an outbreak of flatworms in my 80 gal reef tank. They are small (maybe 1/8" long), oval, beige colored and flat. They do not seem to be bothering any corals though they do get on the snails. I see them mostly on the LR, tank sides and any plastic (powerheads, plumbing, etc) parts. While they are not doing any damage that I can see, they are unsightly and I suppose if the population gets high enough they will cause problems.  <These things are kinda gross, aren't they? Can do damage to some inverts, like corallimorpharians (mushrooms) and similar...> I emailed a MO source about a slug that eats flatworms, they were out of stock but suggested some fish that may also eat flatworms. My question is, which of the fish would most likely do best against flatworms? Would they get along ok with current inhabitants: Bicolor blenny, Kole tang, pair Pink skunk clowns, pair Ocellaris clowns, pair Banggai cardinals (at this moment in a separate breeding tank) and a common Firefish, also an assortment of snails, hermits, Brittlestars, SPS, LPS, soft corals, Long tentacle and Bubble tip anemones. Here is a copy of the response I received, their possible fish list is at the end. <Nice assortment there...> "We are sold out of the Nudibranchs right now, they are called Velvet Slugs. They do eat them, but I added 2 to my 37gallon and 3 to my 100gallon and they disappeared after a few days, I don't think they are real hardy. I've been fighting those flatworms too, hate them, they don't both the corals, but just ugly to look at. <He's not kidding about Nudibranchs not being 'real hardy'. Truth is, they're almost impossible to keep alive in all but the largest, most diverse, carefully managed reef systems. Beautiful, but doomed.> There are some fish rumored to eat them, one or more of these listed do, we added all to our coral system during and outbreak and something ate them all, just wasn't sure which one of these: Sunrise Dottyback Sixline Wrasse Yellow Mandarin Goby Green Mandarin Goby Yellowhead Sleeper Gobies. My hunch is it was the sleeper gobies." <No way. I HIGHLY doubt it was the sand-sifting sleepers. And forget the Mandarin 'Gobies'. These beautiful little guys only eat live, teensy crustaceans, and are incredibly hard to keep because of it. (Big, old, healthy, reef system required). Best bet for munching undesirables is the wrasse, then maybe the Dottyback.> Mostly worried how my blenny will take to a goby as they are similar in body shape and he might see it as a rival. <Your bi-color (love this clown fish!) will probably get along fine with everything listed, and sleeper gobies are incredibly good for your sand bed, if you have a healthy-enough sandbed to keep them fed. Best of all, a small 6 or 8-lined wrasse, or a yellow Coris, is a great addition to most any reef, clam keepers love them for munching on certain clam-munching snails - though a wrasse will likely rule out any future possibility of having a Mandarin, due to competition for foodstuffs. > Thanks! Kathy <A pleasure. Lorenzo>

Re: Flatworms Bob, Just wanted to let you know what I've learned. The Blue Mandarins didn't seem to be making much of a dent on my flatworms. In fact I never saw them go after even one. After doing some more research, I found a recommendation regarding freshwater dips. I took out every piece of coral and live rock, and dipped it for 10 seconds in buffered freshwater, then shook it vigorously for a couple of seconds. Those worms just flew right off. I then scraped my glass, let things settle for a 1/2 hour, and vacuumed the bottom. Obviously even with this procedure, I could not get them all. I restacked and next day received my FF order, which included 3 neon gobies, 4 Scooters and 2 psychedelics, and 1 Scott's Fairy Wrasse (boy is he cool). What was left of my worms are just about gone now. I don't know who did the munching for certain, but my guess is the psychedelics. My corals are kinda shrunken from the dip, but I think they'll be okay. Would you recommend an Iodine addition to help them, (I still use Kent Part A and Part B) or just let things settle? >> Thanks for the input... it probably was... either the Psychedelic or Scooter "blennies" (actually both are of the same family as the Mandarins... Dragonets, Callionymidae). And yes to the iodine dosage... a good idea for traumatized corals. Bob Fenner

C. varians Hi Bob, I have had a problem with the ubiquitous Planaria a.k.a. flatworms, and have purchased two C. varians to try to combat the problem. I have turned off my power heads until I can get foam filters on them, but am wondering if there could be any critter in my tank that might like a C. varians for lunch. Can you tell me what might "go after" my little flatworm eaters? <Any number of worms of different phyla, crustaceans of size if they're hungry. Where did you get this Chelidonura? Bob Fenner> Thanks, Marty
Re: C. varians
Hi again Bob, Well I do have some small crabs that I bought from GARF. I don't recall what type they are so I have attached a pic. Other than some snails, that's it for sessile inverts <Umm, actually these aren't "sessile"... that is, they live on the bottom, but aren't "attached" to it permanently... so they should be able to keep out of the way> other than what's living in my sand bed. As to where I got them, your friends at FFExpress. They were quite pricey, but if they do the job I'll be happy. <We'll see... Bob Fenner> Thanks, Marty

Yellow Planaria Hi Mr. Fenner ! I am looking for a way to control yellow Planaria in one of my tanks. I tore it down, re-set it up and now the little guys are back. I had some come in on a mushroom, in a different tank and I took the mushroom rock out and soaked it in a bucket of salt water at a salinity of 1.030,for about five minutes. This made the Planaria fall off, mushrooms shrank a little. Within a day the mushrooms were big and have never seen any more of the yellow Planaria, in that tank. I have now noticed a new tank critter. I had introduced the "Greek goddess", and the "lettuce " Nudibranchs. Don't know if they ate anything or not. Didn't seem to last to long. My new critter is a tiny long 3/4"to 1/2" white Nudibranch, about 12 at this time. <Interesting> The nitrate is high, <How high is "high"?> no sand in the tank, just live rock. I have a spotted Hawkfish, and cannot tell if he is eating anything or not. Do you have any suggestions on terminating the yellow fellows ? <Yes... would just ignore them.> Do you hear of this popping up with other people? Dealers ? <Other hobbyists mainly... livestock at wholesalers is only there for hours to days> These guys love light, but when corals are in the tank this is hard to cut back on. I know there is a $30.00 Nudibranch who is suppose to eat these guys? Fact ? Is this a new growing problem ? Or a rarity? <No Nudibranch or other animal eats all what people call pest flatworms... many species, varying palatability... unless these ones are causing real grief, leave them be... they will "cycle out" in time.> Now- I wish to thank you for all the hard work that you do in the aquarium industry, as you have modernized it during this computer new age and taken it to places where no fish has swam before !! Keep up the great work as it is award winning !!!! <I feel like Captain Kirk! Make it so!> Sincerely, Jim H. Malone PS. Keep on making NEW WAVES ! <Chat with you soon my friend, Bob Fenner>

Coral Eating Flatworms and need for QT 3/25/03 Dear WWM crew- <cheers, mate> For the last year my Acropora sp. corals have been ravaged by coral eating flatworms (see picture in Julian Sprung's Invertebrates book or The Modern Coral Reef Aquarium).   <yes... quite familiar with it. It is an aquarists penitence for not properly using a QT tank for all new livestock. Its a dreadful lesson to learn the hard way. Please be sure to QT all (algae, plants, fish, live rock, coral... everything) for a simple 4 weeks first. There are several very good articles here on WWM for guidance on the topic from Fellman> I first noticed that areas of my corals were bleaching usually underneath in low flow areas.  Upon closer inspection I noted masses of <1 mm golden brown eggs next to the areas of bleaching.  The worms themselves are cream colored and blend in with the coral quite well.  In their wake they leave a pock-marked appearance to the tissue of the coral and eventual bleaching.  My control methods so far have been to scrub the eggs off (although they can be in rather inaccessible areas) and blast the corals with a powerhead so that the worms come off.  This seems to work better after the coral has been taken out of the water for 2-3 min.  By the way, my Anthias have learned to love eating the flatworms and don't usually miss a single one. <yes... but labor intensive especially for a pest that has direct development (on its prey)> My question is do you know of any other method of control or better eradication?   <nothing surefire... although many have been suggested. Anampses sp. (delicate) perhaps, but only if your tank is large (over 100 gallons), peaceful (fishes), mature (over 1 year old) and preferably with a fishless refugium to support it. These "Tamarin" wrasses have thick rasping lips... advantage over other wrasses> The worms seem to prefer my Acropora valida type corals (aka "tricolor").  They recover after my removal method but within 1 month are back in the same situation.  Halichoeres wrasses seem to ignore the worms (hard to see) and I can't imagine that a Nudibranch would climb on to a coral to get them.  Know anything about "Flatworm Exit"?   <"Coming to a Theater Near You!"> Thanks, John Boe <best of luck, John. Anthony

Acoel flatworms (AKA Rust-brown Planaria) 5/23/03 Hello Crew, <Howdy, Paul> Thanks in advance for taking the time to view and answer my/everyone's questions. <always a pleasure> I have a small 10 gallon tank that houses a maxima clam, a carnation coral, and a branching frogspawn coral.  Unfortunately, the tank is a little limited in flow, so I have a huge outbreak of flatworms. I don't want to keep the tank up and running, will use it as a QT tank once emptied and clean.   <indeed... too small for the frogspawn and anything else in its reach (aggressive) as you know> My question is on transferring the before mentioned livestock to my 90 Gallon reef tank.  I don't want to introduce the flatworms to that tank.   <actually... they are present in most every aquarium (very common)... they just get expressed in some tanks to plague proportions. Quite often mitigated by slow water flow in the tank as you have noted> Can I freshwater dip the clam?   <not at all... will harm or kill it> He is attached to a small rock, so I shake him a bit in a container of sea water to get some of the flatworms to fall off, them dip him, then into QT.  What about the corals?   <just a good thrashing in seawater is fine. Successive rinses if you like. They cannot be eradicated. No worries. Good husbandry in the next tank will likely spare you> What can be done to them to prevent any introduction of the flatworms?   <strict 4 week QT of all new livestock (plants, algae, rock, coral, etc). Most any pest predator or disease can be spotted in the interim> I planned to put all of them into the QT tank for a period of time after dipping or doing whatever was necessary to see if they are clean, then move them over.  Any suggestions? Thanks. Paul <no worries, bud... really a minor nuisance. They wax and wane on their own (months)... can be knocked down singly by aggressive skimming or improved water flow. Many possibilities. An overrated pest IMO. Best regards, Anthony>

 - On Mandarinfish and red planarians - <Good morning, JasonC here...> First, thanks for maintaining this excellent site. Its a truly great resource. <I'm glad you find it useful.> I've read most of the Mandarinfish Faq's and just have one question left that I can't seem to find an answer to.... I have a tank that should be able to sustain a Mandarin.(75Gallon, 115lbs liverock, 4" 1mm aragonite deep sand bed, 30gallon fishless miracle-mud Chaetomorpha refugium with another 20lbs liverock upstream, 20 gallon 4"deep sugar sand aragonite raceway full of Halimeda algae plumbed upstream as well) Both the refugium and the raceway are overflowing with amphipods. My problem is that I have a decent population (not really a plague) of red planarians. (the population is small, sparsely covering only a foot or so of tank during the periodic blooms, then they die back.) I have read that Mandarins eat some types of worms as well as amphipods. Would a Mandarin eat them, and if so is that a bad thing for him? <If I were a mandarin dragonet and given my choice between flatworms and amphipods, I'd eat the amphipods first. That being said, there's just no way to guarantee the fish will do one or the other.> I have read that the planarians are toxic, and wouldn't want the Mandarin to poison himself. <Hard to say for certain... there are many, many types of flatworms that are also red.> Getting rid of the planarians would take only one extra pump, I think, but it would be mounted in an awkward place, so I'd like to leave them alone if I can. -mat <Cheers, J -- >

Yellow wrasse and flatworms 2/17/04 It has been a couple of weeks since  I got a yellow wrasse to take care of some flatworms. I am happy to say that I  can not find any flatworms anymore so either they're all eaten or they are in hiding. <once in a while I'm right about some things <G>> Anyhow, along with the flatworms, the wrasse has also eaten all the little white pods on the glass and rocks (and I had LOTS). <heehee... yeah, they are funny that way. Most wrasses are this thorough on microcrustaceans> How do I go about re-introducing pods into the tank without a refugium? <there is no other way to sustain them with active predation in the tank. That's one of the reasons why refugiums are so very beneficial. I feel most every tank should have one> I was told by my LFS that the wrasse shouldn't be able to eat ALL the pods. <ridiculous> Was wondering if perhaps I don't feed enough. <nope... no worries. This wrasse and so many other fishes would have reduced the pods just the same (Pseudo's, mandarins, etc)> Tank is 55G with also 2 ocellaris and 1 cleaner shrimp and snails/hermits. Feeding is 2-3 times a day alternating between Cyclop-eeze and Spirulina flakes (I think there's enough at each feeding because they stop eating even though there's just a little left). I also feed 2-3x/week some SF bay frozen food (the Marine cuisine blend). Is this feeding regime good enough for them? Thanks. <emphasize frozen foods like the Cyclop-eeze (and mysids, minced krill, fish roe, etc) rather than the brine shrimp based products (weakly nutritious at best). And do look into getting some of the internal refugium kits to help with pod growth. Anthony>

Flatworm- eating Nudibranch Hi everyone. < Hi there. > I noticed my supplier currently has C. varians in stock and thought it would be striking addition to my reef. However, in trying to get some information on them before buying - which there isn't much of - I noticed that this species is widely sought after because of they're flatworm eating abilities. Fortunately, I don't have a flatworm issue - knock wood - and am curious if you know anything about the eating habits of this Nudibranch. < My understanding is that it is an obligate flatworm eater. In other words it will starve without them. > I'm beginning to suspect that flatworms are all they eat, and I have no intention of adding anything to my tank that could potentially starve. Can you shed any light on their eating habits? < I would probably not chance it. Even if it does eat something else, it may still slowly starve. I think Nudibranchs in general should be avoided, and kept for very experienced reefers with mature tanks. > Thanks, Neil
< Blundell > 

Become a Sponsor Features:
Daily FAQs FW Daily FAQs SW Pix of the Day FW Pix of the Day New On WWM
Helpful Links Hobbyist Forum Calendars Admin Index Cover Images
Featured Sponsors: