FAQs about Marine Worms, Vermiform Animals Identification 8 Related FAQs: Worm IDs 1, Worm IDs 2, Worm IDs 3, Worm IDs 4, Worm IDs 5, Worm IDs 6, Worm IDs 7, Worm IDs 9, Worm IDs 10, Worm ID 11, Worm ID 12, Worm ID 13, Worm ID 14, Worm ID 15, Worm ID 16, Worm ID 17, Worm ID 18, See Also: Flatworm ID 1 +, Nemertean, Proboscis, Ribbon Worm ID 1, Nematode, Roundworm ID 1, Nematomorpha, Horsehair Worm ID 1, Acanthocephalans, Thorny-headed Worm ID 1, Tubeworm/Featherduster ID 1 +, Bristle Worm ID 1 +, Hirudineans, Leech ID 1, Sipunculids, Peanut Worm ID 1, Echiuran Worm ID 1, & FAQs on: Worm Behavior, Worm Compatibility, Worm Selection, Worm Systems, Worm Feeding, Worm Disease, Worm Reproduction,  Invertebrate Identification, Worms 1, Worms 2,  Worms 3, Flatworms/Planaria, Fire/Bristleworms, FAQs on: Worm Behavior, Worm Compatibility, Worm Selection, Worm Systems, Worm Feeding, Worm Disease, Worm Reproduction, Related Articles: Worms, Featherduster Worms,

Marine critter ID  -- 07/18/07 Hi Crew, I've written in several times before with freshwater aquarium questions, but this time it's a matter of curiosity rather than fish care. We're vacationing at Bald Head Island, North Carolina. We were out in the sound at low tide and noticed these guys on a sandbar, sticking up out of the sand with about an inch exposed. As best we can tell, they're hollow, flexible tubes made of cemented sand--or made of something else, and very well coated with sand. They're three or four inches at the longest, and never more than three millimeters wide. They look like worm casings, but we've carefully dug around them, rather than just pulling them up, and we've never found anything in or under them. My brother's best guess is horseshoe worms, but the casings aren't U-shaped. In fact, we found one tube with three tubes branching off of it. <I think you've found the tubes of some kind of Maldanidae worm, maybe a "bamboo worm" or something similar. At first I also thought they were parchment/horseshoe worms (Chaetopterus variopedatus). But as you pointed out, they aren't u-shaped and they don't seem quite as tough or big as Chaetopterus variopedatus worm tubes usually are. There are Maldanidae worms which have narrower and more brittle tubes made of sand and mucus. This seems to fit your description and picture. However, I couldn't tell you which species might be common in North Carolina. I suppose it's also possible that these are just old, empty Chaetopterus worm tubes that have just been broken up.> Attached is a picture. Obviously it's not an urgent matter, but we'd appreciate a guess as to what they are! <Btw, this is a cool site for beach findings in North Carolina: www.okeefes.org/Marine_Life/marinelife.htm> Thanks, <No problem. Best, Sara>

Worms in Substrate 10/08 I recently have noticed small (up to 1/2 inch) small white worms with centipede like legs in my crushed coral substrate. Are these harmful to my  marine ecosystem? <Hello there!  They could be any number of marine animals.  However the majority are completely reef and fish friendly and will actually aid in many good processes in your tank.  Not to worry!  Have a good one, Jen S.>

Worm ID, sans pix   9/30/06 I've searched through your worm ID articles as well as other online resources.  I believe I have a worm in my 4yr old tank.  Actually, hehe... I probably have 100's and don't know it.  Anyhow, this particular guy I'd say is at least an inch, or at least that's all that is visible... for all I know he could be a foot long.  Originally, I thought it was the very tip of one of the arms from my burgundy brittle star that I haven't seen since May.  So, the best way for me to describe this guy... burgundy/brown/red, appears to be somewhat flat and is likely slightly smaller than a blade of grass.  I went to pull him out with tank tongs but he quickly retracted into my rock when I touched him. I kept watching and interestingly enough my Coral Banded Shrimp walked right over top of him... the worm didn't retract and the shrimp didn't pick at him.  A picture would be fairly awkward because of his location and the fact that he's pretty small.   From what I've read though, I'd say he's not a segmented worm... <Mmm... actually, very likely of this large grouping... very common... compared to flatworms, roundworms, acanthocephalans...> You seem to suggest from your articles that he's likely more beneficial than harmful?? <The former as a rough guess> If so... cool... I'll let it be.  Just was curious if my description sounded like anything in particular.   I started reading up on spaghetti worms... don't think that's my guy.  Some sort of flatworm perhaps? Regards, Dave Brynlund <Unlikely. BobF>

Serpulid Hitchhiker - 09/26/06 Hi Wet Web Crew, <<Hello Nan!>> I need help (again) identifying a critter/worm in my tank. <<Okay>> Unfortunately I can't attach a picture, but there's really not all that much to see. <<Still...best/is helpful to provide a pic when possible>> Basically I've got a hitchhiker that came in on a small coral frag.  What is exposed of it is about 1/2 in long and looks like it exists in a tiny feather duster tube (the diameter of a coffee stir straw) however it's not a feather duster.  The "head" pokes out and it closely resembles a caterpillar - it even spins a "silk"-like substance and appears to feed by spitting out this "web matter" and then drawing/chewing it back in after I'm guessing it has collected some food particles. <<Correct>> It is predominately white with a touch of pale green.  It doesn't seem to be posing any problems for any other tank inhabitants.  Any idea on what this might be? <<It is a species of calcareous tube building Serpulid worm.  The "web" as you surmised, is comprised of sticky filaments the worm extends to capture/trap detritus...a harmless and beneficial detritivore>> Thanks for your help! Regards, Nan Kramer <<Always welcome, Eric Russell>>

Not so Wacky Hitchhiker  9/9/06 So right now I'm witnessing one of the wackiest hitchhikers I've ever seen and I'm wondering if you've got any ideas what they might be. I just turned out the lights and these two worms (I think) came out and started swimming around the tank like a couple of wrasses on Meth. From a few feet away they look in size, color and general shape a lot like a Neon Eviota Goby. Up close they look a little more like a not so bristly bristleworm - with a sort of black head. the really odd thing is their behavior. They dancing around spinning in circles and flitting about on the acrylic a lot like a moth would do to a light but much faster. I wish I could get a picture but they just never stop moving. Any ideas? Scott <Yep... one of many, many Errantiate polychaetes. There are hundreds of species that "come out" of the substrate at night... Check out some video of "manta ray feeding" on the Net. Bob Fenner>  

Worms in tank  - 09/07/06 Howdy crew!<Hey Kandice, MacL here.> I have a worm question- I tried to identify them myself, but forgive me if the identification was obvious. <You have bristleworms in your tank. Lots of FAQs here on them. They don't look like Fireworms to me from the pictures but I would consider getting a fish that eats them or pulling them out of the tank with some type of tweezers. They can become a problem.> I don't have any fish yet, just live rock.  I think that they are bristle worms, but they don't look as "feathery." They look like aquatic centipedes to me! There are about 5 of them that I can count, about an inch long, maybe 1.5 at the longest.  They all have the same basic structure but vary slightly in color: some are red, red and black, and black and white. If the picture is not good I can try to pluck one out of the tank, however if they are beneficial I would like to refrain from doing so!  Thank you! <I liked to keep some in my tank, honestly because my puffers think they are a delicacy from heaven.  Good luck, MacL>

I have worms! 9/6/06 Howdy crew! I have a worm question- I tried to identify them myself, but forgive me if the identification was obvious. I don't have any fish yet, just live rock.  I think that they are bristle worms, but they don't look as "feathery." They look like aquatic centipedes to me! There are about 5 of them that I can count, about an inch long, maybe 1.5 at the longest.  They all have the same basic structure but vary slightly in color: some are red, red and black, and black and white. If the picture is not good I can try to pluck one out of the tank, however if they are beneficial I would like to refrain from doing so!  Thank you! <Thousands of species as possibilities... Please read here: http://www.wetwebmedia.com/polychaetes.htm and the linked files above. Bob Fenner>

Electric worm in my reef tank!   9/4/06 Dear Mr. Fenner, <Derek> This evening I decided to have a look in my reef tank while the lights were all out, in the hope I might see one of the many creatures that spend the day hidden in holes in the rocks. <Is really a fun, neat time for observation> Well, I saw my boxer shrimp behaving a bit odd, looking like he'd caught something, so I looked closer hoping it wasn't one of my fish. At first I couldn't see anything in his claws but he seemed to be wrestling with something. A moment later two thin strips of vivid electric blue lit up between his outstretched claws and he jumped back like he'd put a pincer in the mains socket. <Ah, yes, phosphorescence... not uncommon in the wild> I continued to watch, trying to adjust my eyes to the dark water, and again a flash of blue, the shrimp jumped back again. Eventually I could see he'd caught what looked like a 2.5" long worm. It was too dark to make out properly, and I didn't want to suddenly light the whole tank up, but the worm looked thin and flat, and while the boxer tried to eat it the worm shot lines of really bright electric blue along its body. <A type of reflex defensive mechanism> it looked like the shrimp was chewing on a live wire, but the most beautiful blue glow. The glow clearly hurt the shrimp, though he didn't give up, and at this moment the boxer appears to have won and is slowly eating the worm. Now that the glowing has stopped the worm looks very plain and could easily be a bristle worm, but do they glow like that? <Can, yes> Whatever this is it has me very excited, I'm amazed to see an unidentified glowing creature in my little reef. I almost wanted to stop the boxer killing it but short of pulling every rock out there was no way I'd separate them, and I also wondered if this worm could be a danger to the fish anyway. I'm a big fan of Wet Web Media and have spent many hours reading through your FAQ's, so when I saw this unexpected and unidentified creature I thought of contacting you first. Have you any idea what it was? <Yes... an instance of (observed) bio-phosphorescence...> Did I get all excited about something common? <Mmm, not commonly seen in captivity> I'm fairly new to reef keeping but to me this felt like some kind of discovery ;) I tried to get it on my digital video camera but it was too dark to see anything. I'd love to know your thoughts. I've tried looking for similar things online but turned up no clues at all. Thanks in advance for your time, and thanks for the great site. Regards, Derek <Do take a look/see on the Net with the term: "biological phosphorescence/luminescence in the sea" in your search tool/s. Bob Fenner> Re: Electric worm in my reef tank!   9/4/06 Dear Bob, <Derek> Many thanks for your reply. I feel very privileged to have seen this if it is not commonly observed in captivity. Now I'm trying to find out what the tiny star shaped white things are on my glass, they look sort of like tiny white starfish (in shape only) but with only 4 stubby 'legs'... they're maybe 5mm in diameter. <Mmm, likely Asterina sp.> I've only ever seen two in the tank (at one time). Any ideas would be very welcome...I'll continue my search on that. <Look up this name> I'm completely fascinated by all the unusual creatures/organisms that appear in or grow on my reef unexpectedly. It's great to have WWM as a resource to help identify them, and to have your personal replies is just fantastic. Thanks again for your time. Best regards, Derek <Welcome. BobF>

Water Movement/Corkscrew Worms - 0/29/06 Good afternoon to all!! <<Morning now...Hello!>> I have a question about water movement.  I have a 55 gal FOWLR with approximately 65lbs of live rock, and a 3.5" DSB.  I have two very old and inefficient powerheads in opposite corners.  The return is a dual return in the middle of the tank, attached to the front of the overflow.  The return pump is a Rio 3100.  I am have trouble with waste accumulations in the "dead" areas, and have to vacuum out every two weeks.  Would the addition of two 475 GPH powerheads, in addition to the Rio 3100, be too much flow in the tank? <<Most any tank will benefit from an increase of water flow if employed correctly so as to not blast tissue from corals/provide a random turbulent flow pattern...so no, not 'too much'>> I am also having problems with BGA,  I have read in WWM that increased flow really helps in control of this nuisance. <<Correct, this alga favors "calmer" waters>> On the flip side, I have noticed several new growths, as well as the addition of copepods.  The growths consist of some white patches on several of the LR, typically on the undersides.  I am assuming these are sponges. <<Mmm, yes...likely Syconoid sponges>> I also have seen many small worms, about 1/4 to 1/2" in length.  These come out after the 10K daylight goes off.  They will get up on a peak on the LR, and launch into the current, spinning in a corkscrew like manner. <<Interesting>> They are pretty much all over the tank and in the Wet/Dry underneath the main tank.  They are white in coloration.  Any clue what these are? <<Have heard/read about similar "sightings" of this worm, what you're witnessing is likely reproductive behavior...I don't know the species but it is harmless if not beneficial>> I would attach pics, but they are way too small to get a clear shot. <<No worries>> Anyway....thanks again for all you do for us amateurs!!! Regards, Jeff <<Happy to help.  EricR>>

Small eel?  8/25/06 Last night, after the lights were out, and we were heading to bed, my husband checked our 55 gallon tank again. He then asked me if I knew anything about a small worm-like thing that could swim in the current. After watching it for a few minutes, we decided to try and net it to remove it from the tank. It was surprisingly easy to catch, and we put it in a small Tupperware type container. Taking a closer look at it, it swims like an eel, is about a three quarters of an inch to an inch long, white in color, with a bluish tip (about an eighth of an inch long) to the tail. Under a magnifying glass, it appears to have a ridge/fin down it's spine. Our tank inhabitants are: 1 clownfish, 5 blue/green Chromis. 1 lawnmower blenny, 1 mandarin, and 2 clown gobies. Plus of course, the cleanup crew, and coral. We put the unknown fella into our quarantine tank for now, until we can hopefully get an ID on him. My digital camera should be returned to me next week, so I can hopefully get a picture of him. Any help with ID in the meantime would be appreciated. Thanks, Jenn <Is likely a worm species of some sort... there are many, and a bunch of these do "come out" at night... Look closely at some nighttime feeding video of Manta Rays... should be on the Net... Youtube.com... see all that swimming wiggling worm-like plankton? Bingo. Not likely harmful. Bob Fenner> - White Worm on Glass 8/21/06 - We have a 75 gallon salt water tank that has been established for approx. 10 months.  Two days ago we noticed a white worm like thing about 1 in long- today when we turned on the lights we noticed 2 more on the glass, but these are about 8 inches long. They are in a crazy form like the design a snake would leave in the sand ( a continuous S shape).  They do not seem to move once they appear.  Are we looking at some type of worm or eggs? <Most likely worms. It's all good, as they say.>  Help!  TS <Cheers, J -- >

What type of sea worm is this?????   8/11/06 Hi Bob, <Koraine> I just came upon your question and answer site when I was looking up different types of sea worms.  My son and I just got back from Mexico and we caught lots of things.  Octopus, stingrays, and lots more,  but it's the first time we caught this weird looking worm thing.  I read about Fireworms, is this that or something else?? <Is a type of Errantiate polychaete... a bristleworm... would have felt like fire had you grabbed it firmly by those lateral processes (notopodia, parapodia...)>   It didn't' hurt us when we held it.  We would love to know.  Please send e-mail with answer, plleassse!! Koraine <Yikes! Glad you didn't get stuck! Bob Fenner>

Identify the worm   7/31/06 Hello Bob, I recently found in the filter sock when do water change there are many little orange or light red worm,  They are about a 1/4" long and kind of little black line in the middle( I use the mag glass to see this).  Could you help to identify it?  does it relate to my sudden dead of my Sweetlips ?  thanks Vincent. <<Vincent:  From your descriptions, they sound like bristle worms (if you do a search, you should find several pictures of them).  If correct, they are fairly harmless scavengers.  However, they can get quite large (several inches or more) over time.  The bristles on the sides will irritate your skin if you touch them.  Best of luck, Roy>>

Trying to identify worm (maybe?)   7/25/06 Hello, all. < Howdy! > First off, I apologize for this almost useless photo, but it's the best I could get. < I could not access it. > http://i18.photobucket.com/albums/b107/bsaastad/aquarium-2006-Jul/mystery-worm.jpg I noticed this thing the other night.  It's right in the middle of the photo just off the upper right edge of the blue mushroom.  If you look hard you can sort of make out what look like fine tree branches emanating from the dark spot.  I've actually seen it before, but always assumed it was some sort of plant, but last night I saw it feeding.  I'm guessing it's some kind of tube worm.  It appears to have a central mouth (Hidden in the dark spot) with fine, multiple branching arms.  The extend, curl up toward the mouth and appearing to deposit stuff, then unroll again.  Just to give a better idea of what I'm seeing, in structure it is reminiscent of a tiny basket star, although I don't believe that's what it is.  This is something that has sprung forth recently - I haven't added any new live rock or even mounted frags in quite some time. Any ideas? < Based on your description alone, it could be a Terebellid sp. worm. Good luck with the photos! RichardB > Thanks, -Brian

Wormy live rock hitch hiker  7/23/06 Hello, I have looked though your whole site for answer, and multiple other sites. <Okay... the whole thing?> I have this worm I saw this morning it could stretch like crazy, was black, maybe 1mm thick if that, and had white blotches. <Neat> It is too small to get a pic, and moves too fast.  I saw it coming out from underneath on of the mushrooms and picking at the LR with a kinda 'fan' mouth.  It would stretch about ¼-3/8s of an in away from the mushroom look like it was trying to pick or tear something away from the love rock, then return back under the Shroom.  Thanks for any help you can offer! <Mmm, some sort of worm... not likely harmful... I would leave as is... enjoy it. Bob Fenner>

Feline worm ID?  7/23/06 While cleaning under my cats food area {which is done every Friday} I found what looked like a white piece of thread.  But it wasn't when I went to pick it up it coiled up.  Then I freaked out because I thought the worst that my cats have worms. Can you tell me if this is a parasitic worm or that it just maybe hitched a ride inside on someone's shoe and that I have nothing to worry about Thank you Ray <Cannot tell you with the information provided. However can relate how I would proceed to find out. Scoop up this worm and take it to your veterinarian. They should be able to tell you of its origins. Bob Fenner>  

Strange Creature   7/2/06 OK, so I've been meaning to ask you guys (and gals) about this creature, but I've only caught glimpses of it until now. Its about 3-4" in diameter and roughly circular. It has no discernible body and when it moves (which it can do pretty quickly), it flows almost like water, following the contour of the rocks. It is grayish-brown, spotted, and very thin. If touched it gets agitated and the edges become very scalloped. I'm sure someone there must know what this thing is. It's certainly interesting. Its right below the orange sponge in the 2nd picture and roughly in the center (towards 8 o'clock from center in the first. Thanks TJ <Good description and nice photo of a resident flatworm. See similar here: http://www.wetwebmedia.com/flatworms.htm Mmm, though many folks seem to panic re such animals presence, I would leave this one be... not likely harmful. Bob Fenner>

Worm identification... ?   6/20/06 Congratulations on a great web site. I was web surfing because I wanted to get some information on a worm I found in my garden, and I don't suppose your expertise extends to the dry world. You don't happen to know of a group that does what you do for earthworms, do you? <Mmm, there must be... have you searched using the fancy term: "Oligochaete"... "Identification"... "Taxonomy"?> Richard P.S. It looked like a worm from outer space! It was lime green, at least 15 cm long but only 5 mm thick, with thin brown stripes running down its length. The most unusual aspect was its head, which was splayed out into a delta shape like a cobra, and which it seemed to be using to explore the terrain. There were no visible appendages, and yet it had no difficulty adhering to a cinderblock wall. Any theories? By the way I live in Japan. <Mmm... this may actually be an amphibian... http://www.amphibiaweb.org/ Bob Fenner>

Worm ID   6/10/06 Hey crew, <John>      I have been stalking this guy for about two months trying to get him out of my tank. Is he just your regular bristle worm? <One of many thousands of species...> The other bristle worms I have seen seem to be red and purple in color, while this monster is yellow and orange. Also, the "bristles" on the side seem to be different than on the other worms. This guy was almost a foot long when fully extended <Yikes... be very careful when not-handling this specimen... use tongs, a net, not your skin... as these podia bristles may be quite sharp, painful... Bob Fenner> Thanks! John

Worm ID 3rd request... ? Still not reading...    5/3/06 Hello, We have this same worm in our tank.  It only comes out at night and retracts very quickly when any light is present so we have yet to get a good picture.  It looks just like these previous two pictures though--it is shiny, bright green, gummy-looking and its head forks in two. <?> It stretches almost the entire length of our tank and stems from the center of the live rock.  I know you said the pictures weren't clear enough but these are the only similar descriptions I have seen anywhere after many, many online searches. What else can we do to help identify it.  Should we try to catch it?  (I hope you say no to that because its totally gross looking!) Thanks, Erica <... I would trap this worm out, likely remove it if it bothers you. Have you (yet) read here: http://wetwebmedia.com/polychaecompfaqs.htm and the linked files above? Do so. Bob Fenner>

Worm ID 4/30/06 I had a Queen conch that was not moving around at all. I picked her up and moved her to another spot. Well at that time she was still alive but still not moving around. Today I picked up the shell after 2 days of her not moving at all and she was gone and a blob of what looked like algae came out it. Well I took the blob and examined it and found it to be tons of tiny worms. They are clear with black bands around them. There were also some all green ones and some red worms. I don't know what to do I found a spot in my LR that has TONS of the clear and black ones. <<It is hard to make an ID without a picture, however it is unlikely that the worms are dangerous if they are living in/on the live rock.  It is more likely that the worms moved in to clean up the conch AFTER it died.  Hope this helps.  AdamC.>>

Unknown Worm (A Cirratulid Polychaete I Believe) - 04/20/06 Bob, <<EricR here>> First off thanks again for the advice with my tank, I've done a few extra water changes and everything seems to be running perfectly fine.  I mentioned in my last email that I was going to try to get a few pictures of this worm I've found to maybe come to a better conclusion as to its species.  I think I might have seen it before when reading the sites on your site, but I can't seem to find it again.  Either way here are 3 pictures of this awkward looking worm.  Looks to me like maybe he needs a good barber. <<Mmm, your comment is more intuitive than you probably realize.  What you have here looks to be a Cirratulid polychaete worm...commonly referred to as a "Hair" worm...often confused with/misidentified as a "Spaghetti" worm (a Terebellid polychaete). What do you think? <<A beneficial detritivore...I'd keep it <grin> >> Thanks again, Anthony <<Quite welcome, EricR>>

Flatworm ID - 04/19/2006 Hello and greetings from sunny Woodland Hills CA, <Hello.>    Please accept my apologies for not sending this directly through your website link - somehow I managed to type-in the outgoing server information wrong and now I can't seem to correct the format in my computer. <We've gotten it just fine.>    I want to thank you for your website; it is an excellent resource for novices like myself trying to create the most natural environment possible for my marine pets. <Thank you, we're happy to help.>    By way of background, I have been keeping a 40 gallon hex tank the "old school" way (undergravel filter and dead coral skeletons) for years with some success. I recently woke up to the new techniques available and upgraded my tank to live rock (plus protein skimming, vigorous water movement and addition of a 96 W power compact light and UV sterilizer). Unfortunately, I had some trouble along the way keeping water temperature stable and had to remove all my fish to quarantine for Ich treatment. <Ouch!> Right now, I am in week 4 of a (minimum 12 week) fallow period. The tank still contains a small Diadema urchin, two cleaner shrimp, one Peppermint shrimp and a small colony of zoanthids (live rock stowaways) which are all doing very well. Ultimately, I would like to add back a few fish in this tank, plus a small green star polyp colony currently in quarantine (also a live rock stowaway) and maybe some mushroom polyps later. <Ok.>    Due to the stress of having to remove everything to catch and quarantine my fish, the tank had to recycle through its algae cycle. It is through the diatom period and nearing the end of the Cyanobacteria phase. The tank now is going through a hair algae bloom, which is subsiding. Water chemistry is excellent. Now for my question - over the past week or so I have been noticing ever increasing levels of what appear to be small slugs or snails grazing on algae. They are about 5-10 mm long and a translucent white-blue color. They seem to be soft bodied with an internal "shell". Photos are attached. Would you kindly advise if you can help identify and provide any pertinent information. <This is a flatworm. Perhaps Amphiscolops sp.> If this is a reason for concern or fish food later? <Harmless. Here's some more info. http://www.wetwebmedia.com/flatworms.htm > They are definitely multiplying pretty fast. <Can reproduce by splitting. They can't really exist in high flow areas though, are they growing quickly in dead flow areas? Likely won't last too long.>    Thanks in advance for your reply. <Hope it helps some.>    Scott (AKA Shark Bait) <Josh.>

Re: Flatworm ID - 04/24/2006 Thanks for your help Josh, <Glad to Scott.>    From the photos, your reply appears to be spot-on. <Glad to hear.>    Sorry for asking about something so well covered on your website (I just did not think to check in the sections covering flatworms -beginner's mistake!). <No worries.>    I see from further reading that this critter eats copepods; this makes sense as I did notice a "bloom" of small copepods on the tank wall earlier that now seems to be subsiding. <Ah, the balance of nature.>    In response to your question, the tank has pretty vigorous water movement (roughly 10X tank volume). I'll keep the water moving in the tank and see if copepod/Acoel balance reaches a kind of equilibrium. <It will I'm sure.>    I read somewhere that six line wrasses eat some types of flatworms (this is one of the fish I plan to add later) - do you know if this Acoel is a food source for a six line? <I'd say it's a good bet.>    Regards (and thanks again), Scott <You're welcome (sorry for the delay) - Josh>