# What worm is this? (several pics)



## Diana (Jan 14, 2010)

I do not know what sort of worm it is, but this post is a very good warning to always quarantine new fish. 

Poor Oto, that is a giant worm compared to the size of the fish. :eek5: :icon_cry:


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## PlantedNewt (Mar 19, 2012)

I hate worms so much. I'd like to know what that is too. Someone enlighten please!


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## mistergreen (Dec 9, 2006)

Yeah, seems like you have some mysterious parasites in your tank from your previous threads. It's not segmented so it's not a leech. I'd go with a round worm or flat worm (planaria type).


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## Complexity (Jan 30, 2008)

I'm trying to figure it out. So far, I haven't found a match for it yet.


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## mistergreen (Dec 9, 2006)

Save that worm so you can experiment on what type of dewormer can kill it and then treat the whole tank.


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## Complexity (Jan 30, 2008)

mistergreen said:


> Yeah, seems like you have some mysterious parasites in your tank from your previous threads. It's not segmented so it's not a leech. I'd go with a round worm or flat worm (planaria type).


We were crossposting! I don't think this is from my tank since this was on a new oto I just bought. So this most likely came from the wild (aren't most otos wild caught?).

Okay, so it's not a leech. It doesn't have the pointed head like a planaria, and it's definitely not flat so I think that rules out flat worms (planaria). I looked at roundworms, but didn't see anything that matched.

The thing is this worm was under the oto's skin. Not in the intestinal track, not the anas. Just under the skin below the eye, but above the soft part of the upper underbelly of the oto.

Maybe it's not a true worm. I wonder if it could be some kind of larva?


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## Complexity (Jan 30, 2008)

mistergreen said:


> Save that worm so you can experiment on what type of dewormer can kill it and then treat the whole tank.


Not knowing it would be so hard to identify, I had already let it dry out. I'll go put it in a jar of aquarium water, but odds are, it's dead.


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## Complexity (Jan 30, 2008)

What about flukes? At first glance, body shape looks about right. Would it be possible for one to be curled up under the skin below the eye?


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## Complexity (Jan 30, 2008)

From all that I have read and seen so far, I think the worm is a _Trematoda_ (fluke).

Since the worm is now dead, I was able to get a better view of it under the microscope, including viewing it upside down. That allowed me to see the internal structure better which I was able to match to pictures of flatworms on the internet.

Of the three main flatworms (planaria, flukes, tapeworms), not only do flukes seem to be a better physical match, but they are the best match for it being under the skin of the oto.

Therefore, I'm going to identify this worm as a fluke and look into what needs to be done to safeguard and/or treat the other fish.


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## Complexity (Jan 30, 2008)

Yeah, yeah, I know. I'm talking to myself now. :biggrin: Well, maybe this will be helpful to someone else down the road. :smile:

I think I may have figured it out. And if I'm right, then it's actually good news!

I found this article which explained flukes in detail, but in terms that fits the aquarist: http://www.skepticalaquarist.com/parasites-flukes

Close to the bottom, the article describes "Digenetic or Digenean Trematodes: "Grubs" or Flukes." The description matches the worm (grub) i found on my oto. The article is so good, I'm going to quote the applicable section so it's always available here.

_Emphasis original to the article except the parts in red which is what I think applies to the worm in my oto._

*Digenetic or Digenean Trematodes: "Grubs" or Flukes.* These form a separate and also entirely parasitic division of the flatworm phylum. Don't confuse them with the skin and gill flukes, which are _monogenetic_ trematodes, or with the harmless free-living planarians you can see. Digenetic trematodes have complicated life-cycles that involve two ("_di + genera_") — or even four! — hosts in succession. Fishes play only one role in their parasitic lifestyles, either as an intermediate host or as the final host.

Digenetic trematodes aren't treatable. Fortunately they can't complete their full life cycle in the aquarium. Your pond-raised fish may arrive bringing encysted trematodes with them. Otherwise, the trematodes' entrance to the aquarium is through their first intermediate host. Generally this would be a pond-raised snail, but infected copepods might possibly come in with pond-raised plants. To become infected, the snails or copepods would have to come from an outdoor pool that is visited by fish-eating birds, such as kingfishers or herons.

Fish farmers are interested in protecting their stock from predation, though, and many outdoor fish farm pools are protected with heron nets. The adult parasite's eggs are passed out in the bird's feces, develop first in the snail, pass back into the water and then make their way through the fishes' epidermis. The fish doesn't have to eat the snail.

Once in the fish, the trematodes take one of two directions, depending on which taxonomic group they belong to. If the fish is their final host, they establish themselves in the intestine, where they can do a lot of damage and even block the intestinal passage of a small fish. The unlucky hosts of those digenetic trematodes don't survive long. If on the other hand a warm-blooded fish-eater is to be the final host, however, the flukes will encyst themselves (as "metacercariae") in the flesh of the fish.

There are three main kinds: Black grubs (_Uvulifer spp._ and their kin) form "black spot" cysts like pepper-grain pimples visible under the skin or in fin membranes or in the muscles. The minimal physical damage they do is over by the time the cysts have turned black. White grubs (_Posthodiplostinum spp._ etc.) encyst inside organs such as the kidneys, liver and heart, and you don't generally see them. The larger yellow grubs (_Clinostomum spp._ et al.) encyst in the muscle tissues, where you might have found them while filetting freshwater fish. I found an accessible and very informative USDA technical bulletin, a biologists' report on these trematode "grub" parasites: "Biology, prevention and effects of common grubs [digenetic trematodes] in freshwater fish".

So, that's why the randomly-scattered black pinhead-sized spots under the skin or the lumps you'll sometimes find embedded in the musculature of fishes that have been wild-caught or have been raised in outdoor ponds, will sometimes enclose a dormant curled-up worm (the cercaria in the metacercaria), ready to be released inside a fish-eating otter or bird — or a goldfish-swallowing bachelor-party jokester! As I said, none of these encysted metacercariae are susceptible to medication. But they won't spread in the infected fish either, nor infect other aquarium fish.

In aquaculture, ponds are periodically emptied, dried, and limed with quicklime to eliminate digenetic trematodes.​I would definitely call the area where I found the worm a cyst. And if you look at the pictures of the oto, it did very little damage, just as the article states. The worm was curled up inside the cyst when I popped it open. I think the oto died for the same reason many newly purchased otos die -- their mortality rate the first month is well known to be poor. The worm did not kill the oto. I just happened to discover the worm because the oto died.

I can't be 100% this is it, but it sure does sound like it. Everything matches. The best part of it is there's no need for any kind of treatment. They cannot finish their life-cycle in an aquarium!


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## Complexity (Jan 30, 2008)

Okay, I'm really sure I have it identified. It's one of the yellow grubs in the _Clinostomum spp._ What nailed it for me was a match in the picture below. When I looked at the worm in the microscope, it looked just like worms *T* and *V* in this picture (especially *V*).









http://www.fao.org/docrep/008/v9551e/V9551E14.htm

Turns out *T* is Met. of _Clinostomum tilapiae_ (length 4–8 mm) and *V* is Met. of _Clinostomum_ sp. (“cutaneum”) beneath the scales of cichlid fish (length 6 mm).

Even the size of the worms match.

That's it. I think that's the identification of the worm. roud:


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## Heartnet (Sep 13, 2009)

I know you identified the worm already, but I have to commend you on the excellent quality of your descriptions, pictures, ID methodolody and your follow up posts. It was very informative and detailed for a fluke. 

Glad to know it doesnt pose a serious infestation threat. 

Sent from my SAMSUNG-SGH-I717 using Tapatalk 2


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## mistergreen (Dec 9, 2006)

Yup, I think you found it. So these guys are the cysts in your cardinals too.
I've killed planarian with levamisole before so maybe it'll wipe these guys.

Seems like a carrier for these are ramshorn snails. I'd remove any I see.


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## driftwoodhunter (Jul 1, 2011)

I subscribed to this thread immediately after you started it, I'm so glad I did! The fact that you added the illustration is icing on the cake - I love visuals, although the pics of the parasite did creep me out - lol.

The line I quoted is by far my favorite. It seems so rare not to have to worry about a whole tank infestation...



Complexity said:


> none of these encysted metacercariae are susceptible to medication. But they won't spread in the infected fish either, nor infect other aquarium fish.


Thank you for taking the time and the diligence to share all of this info to us : )


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## Overfloater (Jan 12, 2004)

Since you identified the parasite, did you figure out what the hole was?


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## Complexity (Jan 30, 2008)

mistergreen said:


> Yup, I think you found it. So these guys are the cysts in your cardinals too.
> I've killed planarian with levamisole before so maybe it'll wipe these guys.
> 
> Seems like a carrier for these are ramshorn snails. I'd remove any I see.


Yeah, I believe these are the the same thing that I've seen in my cardinal tetras for all these years. (For those who don't know what I'm talking about, I'm referencing this old thread: http://www.plantedtank.net/forums/showthread.php?t=70100.) This explains why those spots would never disappear, but also never harmed the fish and never were contagious. They're "grubs" just waiting for the fish to be eaten so they can continue the next stage of their life-cycle which can't happen in an indoor aquarium. I had no idea I'd resolve this old mystery when I found the dead oto!

I don't have any ramshorn snails so these grubs are already on the fish when they're caught from the wild. That also explains why I only saw them on my cardinal tetras since they're generally wild caught (just like otos). My guess is that they start out too small to be visible to the naked eye, but develop large enough to be seen over time. If I ever have a cardinal die that has one of those spots, I will most definitely open it up to confirm the diagnosis.

One of the articles I posted (I think it's the Skeptical Aquarist article) stated that you can't kill these grubs so I don't think there's any point in dosing anything in the tank specifically for them. However, if you have to dose the tank for another reason, please let me know if you see any affects. I think the main course of treatment, if one is desired, would be to open up the cyst and physically remove the grub. Since the grub isn't causing a lot of damage to the fish, it would only cause a surface wound on the fish from which the fish should be able to heal as long as protected from secondary infection.


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## Complexity (Jan 30, 2008)

driftwoodhunter said:


> I subscribed to this thread immediately after you started it, I'm so glad I did! The fact that you added the illustration is icing on the cake - I love visuals, although the pics of the parasite did creep me out - lol.
> 
> The line I quoted is by far my favorite. It seems so rare not to have to worry about a whole tank infestation...
> 
> ...


Thanks! I bought my microscope a few months back and have really enjoyed having it. There is no way I could have identified this worm (grub) without it.

If you think pictures of the grub creeped you out, just imagine how I felt. I pulled that oto out of my 75g tank! I know all about using a QT, but chose not to for a number of reasons, and then had to face the sinking feeling that I may have royally screwed up my entire tank. You have no idea how relieved I was when I read the part about the grub being unable to complete its life cycle in the tank. Whew! I escaped a bullet with this one.

I think the other really interesting thing about this is that it shows it's not a good idea to immediately start dumping medicines into a tank at the first sight of something foreign since, as in this case, meds may not only be ineffective, but also be unnecessary.



Overfloater said:


> Since you identified the parasite, did you figure out what the hole was?


Yeah, that's the grub's mouth/anus/opening. I could see it much better when I was able to view the grub upside down (which is where the hole opens up). I ran across a pic that labeled all the parts, including the hole. If I can find it again, I'll post it. That hole was very helpful with the final identification of the grub.


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## Complexity (Jan 30, 2008)

Well, I can't find a labeled picture of the _Clinostomum_ grub, but in general, the hole is called a "sucker". All Trematodes appear to have at least one of them. You can see them labeled in the pics on this page: http://dc368.4shared.com/doc/Xlm9X6SI/preview.html

Here's a good picture of the structure of the _Clinostomum_ grub. You can see how well defined the sucker is. I was able to see it very clearly under the microscope, including the triangle opening with the round structure surrounding it.










Picture source: http://dailyparasite.blogspot.com/2010/10/october-21-clinostomum-marginatum.html


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## wkndracer (Mar 14, 2009)

1st flubendazole, 2nd levaisole both can be water column dosed in planted tanks and most everything's covered for parasites.


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## Complexity (Jan 30, 2008)

wkndracer said:


> 1st flubendazole, 2nd levaisole both can be water column dosed in planted tanks and most everything's covered for parasites.


Thanks, but treatment is not only ineffective, but unnecessary in this case since the grubs cannot complete their life cycle in an aquarium.


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## Williak (Jun 26, 2012)

Very informative and excellent investigation! Now I feel bad for not autopsying all my passed fish :icon_neut


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## ETK (Jan 25, 2013)

I know this thread is a bit old, but do you think this is the same as what I am dealing with? There is some nasty thing in the gills of one of my black phantom tetras.

Anything I can do to confirm or rule it out?

Since my fish isn't dead, is there anything i can do for it?

Thanks.


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## VAtanks (Feb 1, 2013)

Fluke treatment is carried out using potassium permanganate. You can either bathe the sick fish in a potassium permanganate solution (10mg per litre water) for about 20-30 minutes or treat the entire holding [COLOR=black! important]tank[/COLOR]. Treating the entire tank will help make sure that you kill all flukes and help you avoid a new fluke problem, but it will be a little messy as potassium permanganate will color the water in the aquarium. Despite this I recommend the later option as it is safer and doesn't involving catching the sick fish and subjecting it to extra stress, and because it helps make sure that all flukes are eradicated.


quoted from http://www.aquaticcommunity.com/disease/flukes.php


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## VAtanks (Feb 1, 2013)

warning though adding potassium permanganate to your tank will turn your water pink...to almost a purple color the higher the concentration.


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## ETK (Jan 25, 2013)

Thanks for the recommendation. I have some praziquantel that I ordered a few days ago -- i think i will try that since it is also supposed to work on flukes.


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