Flatworm - Acoel Planaria

[jthomps123]

Update on my red/rust flatworms. They still continue to accumulate in my sump in epic proporations, but have been invisible in the display tank. I attribute this to my green mandarin, who is extremely fat.

[Craig Manoukian]

Great news, about the Mandarin of course!

[tomshannon]

Originally Posted by leahski

so you recommend that they need to be disposed of? i wasn't sure if they really posed any threat to my tank since it will be softies and a goby...no acro or sps.

Hi Tori,

In answer to your question(s), and given that you have Convolutriloba acoels (rust/red flatworms) they don't pose a threat to your tank despite conventional "wisdom". I answered a similar question on another forum site but will repost it here as well:

Bear in mind that I am only speaking on behalf of Convolutrilobids...

1) Will they damage my corals?

Absolutely not. Contrary to popular belief they do not feed on coral tissue, nor do they obtain their algal symbionts from corals, through consumption or otherwise. The acoel symbionts are "green" prasinophyte algae, most likely Tetraselmis sp. Corals, on the other hand, harbor "brown" dinoflagellate algae of the Genus Symbiodinium. Convolutriloba feed on tiny crustaceans or crustacean larvae, rotifers, and other tiny invertebrates; not diatoms, as is commonly assumed. They are ambush predators.

2) Will they eat something beneficial?

Depends on what you're calling "beneficial". Will they eat the pretty macro-stuff in your tank? No. They will, however, compete with other critters in your tank for resources such as copepods, Artemia, etc., but no more than any other carnivore/omnivore. The main difference that becomes apparent rather quickly is that their population growth responds much faster to changes in resource (food) availability than that of larger "desired" invertebrates and fish. Please note, however, before worrying that they will starve out your corals and wipe out your copepod populations, that their numbers will fall in response to resource scarcity just as quickly as they rose in response to resource abundance.

3) Will they produce toxins when they die?

No, but they will if they are killed. When food is scarce the acoels will begin to starve, and just like most other animals, starvation leads to rapid weight loss. The Convolutriloba cannot survive indefinitely on algal photosynthesis alone. Before these animals die from starvation, they are so small and depleted that upon their death their bodies contain little or no toxin. When the acoels are killed, however, be it by chemical warfare, salinity changes, temperature changes, predation, maceration, or squishing, they will release a potent toxin and make life pretty miserable for the other tank denizens... Food for thought: the death of a medium-sized tang, if unnoticed, will cause a spike in a tanks ammonium levels and make everyone's lives just as miserable; but you never hear anyone preaching to KILL KILL KILL all medium-sized tangs.

4) They're ugly & icky.

So's my aunt. She's even got a moustache, but I'm not about to condone her eradication or banishment from the biosphere. Beauty is in the eye of the beholder.

5) Reef wisdom says they will block sunlight from corals.

Reef wisdom ain't as wise as it thinks it is . For the most part, Convolutriloba don't like hanging out on coral; corals sting. They are more often found along the bottom edges and corners of tanks, on live-rock outcroppings, or just outside of shadows on the substrate. This isn't to say that they never climb onto corals (certain Sarcophyton capitulae seem to attract them at times), but unlike some Waminoa species, it's not their usual modus operandi.

6) A year or two is too long to wait for most hobbyists.

That is how long it usually takes for a population to die off on its own. By no means does this imply that one will have gazillions of Convolutriloba for two years, then suddenly none. Again, the populations wax and wane according to resource availability. The best way to keep the numbers in check is to know your system; know how much food is enough to keep everything in your tank happy and healthy; and don't feed it any more than that. By carefully monitoring the addition of food, everything in your tank benefits and you won't experience large-scale population explosions of Convolutriloba. Eventually they'll just slowly wither away to nothing .

[Craig Manoukian]

Very good information Tom!

[Basile]

I can just tell what happen and how i got rid of them, no special insite for that problem. I just siphon them when ever i did a water change, manually took them out with a air tube and out of the tank. They finally vanished. Not sure if the population crashed like i was told it would, but i'm free of them. No chemical used, but i'm sure if the problem had persist for months i would of had to use something, but i always try the natural way first. Anyway thats my experience with them.

[rmlevasseur]

4) They're ugly & icky.

So's my aunt. She's even got a moustache, but I'm not about to condone her eradication or banishment from the biosphere. Beauty is in the eye of the beholder.

Yea, but you didn't put your aunt in your tank.

[Shells]

Hey guys.
I'm back after a long absence. i'll tel ya why in the off topic forum, but now, i"ve got an over population of red flat worms> i added two Manderin fish and have noticed a slight decrease in their numbers, but i'm told it will take time. i'm thinking about adding one more> my system has been up for over 4 years, so i'm not worried about natural food for them, they are fat and happy.

[jski711]

what type of mandarin did you add?

Jake

[rmlevasseur]

I recently treated my 180 with Flatworm Exit, and I couldn't be happier with the results. I followed the instructions on the box and did a major major change a day later, followed up by another one about 5 days after that.

I also have two mandarins and a 6-line. I think they they may have slowed them down, but I never actually see them eat one.

I did not lose a single fish or coral from the treatment, but it did seem to result in the loss of a few turbos. Snails don't like it, but only only appeared lethal to a few of the turbos. Others survived fine, although they appeared "stunned" for a while.

I did not need to do a follow-up dose. Three weeks later and still not a trace of a single flat.

[leahski]

Update:
after a long absence i'm getting slowly back into the cozy RS family and i thought i'd give an update of my condition.

my sweet little 8 gal, which was once overrun by gross crawly red flatworms (i'm talking EVERYWHERE!!) is now basically flatworm free. it is a rare ocasion when i see more than one on the glass, and they no longer are visible on the substrate and/or rocks.
what did i do? nothing.
seriously. regular water changes.
i tried siphoing them off and trapping them in a pad of filter floss then putting the water back into the tank and while it made me feel better for a bit to see all those nasites squirming in about an inch of water, it didn't help the problem at all (at least not that i could tell).

so all of you battling the wreched planaria, take hope. they won't be there forever.

[ReefGuy69]

Well i can be added to the red rusty Flatworm club. I noticed a few on the glass this past weekend. i thought nothing of them. At the time i thought it was just little red slime things left by snails or something. Tonight i was staring into the tank and i noticed more on the glass and a few on the rocks. I also noticed one or two on my sand sifting star. Will he be ok? I am debating getting a 6 line wrasse. I was going to eventually get one anyways. or im debating doing Heinz's total darkeness for 2 days method. In theory it seems it would work. Has anyone else here done with method with success? it seems easy enough. I have carbon on hand and i can go to town siphoning. I dont have a mass outbreak yet. but i would rather get it now then when i have a full blown outbreak. Im thinking Ill do the 48hr darkness and then addthe 6 line wrasse once i light the tank back up.

[Woodstock]

Do try the 48 hour darkness. I would love to know if that is successful. Heinz is extremely knowledgeable so it probably will work
Let us know how it goes!

[ReefGuy69]

I will. Starting tomorrow (Thanksgiving) I will be giving thanks back to the FLATWORMS by starving them of all light sources for 48 hrs straight. I will be running Carbon in my Phosban reactor and skimming the entire time. and i will also be using a micron sock to catch any dead ones floating in the water column. Luckily it will be placed in my sump right next to my skimmer so im hoping any toxins will quickly get taken from the skimmer and carbon. Wish me luck.

[ReefGuy69]

My tank is in Dark Mode. Completley Darked out. All lights are off and unplugged and i have a sock to catch the little boogers. My skimmer is going and i have carbon on hand and water for a salt change. I dont have a full outbreak so im hoping all goes well since im doing it very early in their development. Wish me luck... oh and Happy Thanksgiving All!!!

[ReefGuy69]

its still dark.. I just hope the fish are ok. Im scared to look in then i would have to let some light in and i dont want to let one flat worm get some light and be able to survive and blow this whole thing. Keeping my fingers crossed everything is ok. i really hope this works. I have a bunch of family coming over saturday and they will want to see the tank. wont be cool if all my fish croaked.