# What are these? Worms, slugs, or worse..



## Mer_

Hi!

Recently I have been finding a few of these in my large display terrarium. It has been set up for a year and these are just appearing. Can someone tell me what they are and what the best way would be to get rid of them?


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## kimcmich

Greetings,

It's hard to tell from the images whether these are small slugs or flatworms. In either case, sadly, they are not easy to eradicate short of a kill-everything-that-breathes CO2 bomb.

Did these guys look different before they were collected? Were they more extended?


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## Mer_

kimcmich said:


> Greetings,
> 
> It's hard to tell from the images whether these are small slugs or flatworms. In either case, sadly, they are not easy to eradicate short of a kill-everything-that-breathes CO2 bomb.
> 
> Did these guys look different before they were collected? Were they more extended?


I collected this particular one off of the glass. On the glass it looked slightly extended and was white, however that could have been because of the light shining through its body.


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## kimcmich

Was the "head" fairly blunt ended when it was crawling freely on the glass or did it taper to a fine point the animal waved around as it crawled? How long are we talking here?


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## Mer_

kimcmich said:


> Was the "head" fairly blunt ended when it was crawling freely on the glass or did it taper to a fine point the animal waved around as it crawled? How long are we talking here?


Here is a picture of it on the glass. I'd say a little less than half inch


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## Mer_

They seem to have a pointy head that they wave around


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## kimcmich

OK - you've got flatworms - perhaps Rhynchodemus sylvaticus which is the common pest in the hobby. It can come in with your plants, substrate or other items. These guys actually have their "mouth" midway along their body - which I think is visible as the darker spot in your latest image.

As I mentioned, you will not have an easy time getting rid of these. Repeated CO2 bombs might work - but they are quite an undertaking; can damage plants; and require all animals to be removed from the viv during the process.

These flatworms are predators of arthropods and they are quite capable fruit fly predators. They will also eat your microfauna. That said, I have them and still have microfauna.

Some claim that giant orange isopods will help control their numbers but this is only anecdotal.


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## Mer_

kimcmich said:


> OK - you've got flatworms - perhaps Rhynchodemus sylvaticus which is the common pest in the hobby. It can come in with your plants, substrate or other items. These guys actually have their "mouth" midway along their body - which I think is visible as the darker spot in your latest image.
> 
> As I mentioned, you will not have an easy time getting rid of these. Repeated CO2 bombs might work - but they are quite an undertaking; can damage plants; and require all animals to be removed from the viv during the process.
> 
> These flatworms are predators of arthropods and they are quite capable fruit fly predators. They will also eat your microfauna. That said, I have them and still have microfauna.
> 
> Some claim that giant orange isopods will help control their numbers but this is only anecdotal.


Are they harmful to the frogs?


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## kimcmich

This species of predatory flatworm is too small to be harmful to the frogs. They might even be frog food though they tend to be nocturnal. If you see some during the day it may mean you have a much larger population that comes out at night.


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## Louis

kimcmich said:


> Some claim that giant orange isopods will help control their numbers but this is only anecdotal.


Anecdotally I can tell you that there are also some small soil dwelling species of rove beetle that wouldnt harm frogs but do prey on these.
I have used two species, Atheta coriaria which is available as a biological control for fungus gnats in greenhouses, and another slightly larger (still <1cm) and more elongated species isolated from some leaf litter. 
The larvae and adults of the latter in particular seem to prey aggressively on anything that even resembles a worm and happily tackle prey larger than themselves.
Now I believe the beetles also prey on springtails and probably isopods to a lesser extent but they've never wiped them out in any tank I've added them to and I do see reports of flatworms completely annihilating peoples microfauna.


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## kimcmich

@Louis,

Can you elaborate on your experience with the rove beetles? I imagine they eliminate earthworms too? Do you have direct experience with them eliminating/controlling terrestrial flatworms in your viv? I read your comment in another thread about these - I just wasn't sure if you'd used rove beetles to solve this pest problem specifically.


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## Louis

Both the beetles I've used are tiny so I don't think they'd tackle a fully grown earth worm but the larger of the two certainly preys on babies I've offered them from my wormery. 
Obviously I don't know the exact species we're dealing with in this thread but they have certainly eradicated a similar flatworm in one of my tanks along with literally anything else that left trails through the condensation on the glass - that's how I know they're gone.
Unfortunately the slightly larger species I collected from the wild and haven't been able to positively ID yet. They're extremely elongated and fairly flattened to the extent that when they move it almost looks serpentine as they 'flow' over obstacles. Once I do and can get some good pictures I'll probably make a thread but the same protocol for breeding Atheta coriaria seems to work for them.


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## kimcmich

@Louis,

Alright then - I've ordered myself some Atheta coriaria. I think I'll test feed them some flatworms before adding them directly to my viv. I would love to decimate these flatworms  And at an adult size of 3-4mm, these guys could even be frog food...


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## Louis

I'm going to feel terrible if the beetles now end up eating your cat or something but good luck! let me know how it goes. Remember they are predators that will potentially also eat springtails and eggs so don't add hundreds to any one tank. 
In the vivarium I most recently set up with these I think I initially added around 6 of each species and they are breeding as I see larvae.
here's a useful document on how to maintain a culture so you have them on hand as an extra feeder if your frogs do like them.
https://cerestrust.org/wp-content/uploads/MSU-Rearing-Dalotia-coriaria.pdf
My geckos love them but the beetles can fit into tiny cracks to hide. Being so flattened I think they are very adept at hiding under bark.


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## Mer_

kimcmich said:


> This species of predatory flatworm is too small to be harmful to the frogs. They might even be frog food though they tend to be nocturnal. If you see some during the day it may mean you have a much larger population that comes out at night.


I have noticed a decrease in their numbers. I think there is the possibility that the frogs might be eating the juvenile worms while I kill any of the larger ones that appear.


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## kimcmich

@Mer_,

I hope you do have flatworm-eating frogs (maybe your frogs can offer training classes to the rest of us). These worms are active mainly at night (though you will see a few adventurous individuals during the day) so a daytime census will not give you an accurate picture of the population.


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## Entomologist210

As far as Coleoptera go, I've got keys for days yo. So if you have some good pics I can probably ID it.


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