# Controversy: Planaria vs baby shrimp



## Piscesgirl (Feb 25, 2004)

I've found two references while searching the Internet over the last several months that suggested that Planaria were toxic to shrimp (one is an article devoted to just that). I posted that question on two mail lists, all answers denying such a connection. However, I have my suspicions. Baby shrimp are not much larger than brine shrimp, and many references are that planaria will eat brine shrimp. So, I leave it to your thoughts, discussion, and ponderings...do those of you who might have planaria in your tanks notice few or no young shrimp?

Also, I've had a huge reduction in my Crystal Reds, having not paid great attention to them in quite a while -- and it could be 1). The planaria, and 2). Very low kH (possibly zero) as my water is soft and I hadn't been adding the Calcium Carbonate as I should have. Cherry Shrimp population, however, is just fine. No tiny babies, but some younger ones. I saw one tiny baby Crystal Red the other day, haven't seen him since. I worry he's been a victim of the planaria. 

Attached see a picture of a planaria on a Crystal Red I took several months ago. After the picture was taken, I used a bamboo skewer to knock the planaria off the shrimp. The shrimp had trouble moving following -- almost as if it was paralyzed. Notice the pale coloration.


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## richy (Nov 8, 2004)

i've never heard of such a connection between planaria (white sine-wave worms?) and shrimp before. i have seen from personal experience some ghosties grabbing and eating planaria (that is, if we're talking about the same thing), so i don't know if this is possible or not. are you suggesting that planaria are possible parasites that latch onto shrimp?


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## Piscesgirl (Feb 25, 2004)

I don't think they would affect most adults unless they are weak or sick (possibly my shrimp was weak already, above?), it's the baby shrimp I worry about. I again have read accounts where planaria will eat brine shrimp, which to me is tantamount to baby shrimp.... But, I'm not sure this can be proven....


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## Piscesgirl (Feb 25, 2004)

http://www.aquarticles.com/articles/management/Ali_Planaria_Worms.html

This is the article I found...look partway down the page.... but can't find much other than this except one comment on a shrimp forum stating similar.


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## gnome (Jan 27, 2004)

I saw that article a few months back when a link to it was posted on the APD. I think anything is possible (BTW, where is the planarian on the photo of your shrimp, Piscesgirl? Is it that blurry gray mass on the "tail"?). 

Hydra, when present, probably do more damage to artemia populations than planaria, but I don't know. Seems to me that if it's true about planaria secreting toxins, then they would pose the most immediate risk to small shrimp that have just molted.

I just started noticing those disgusting things slithering along the glass of my 2.5-gallon tank a few weeks ago. I introduced some small guppies from another one of my tanks into this one, and they ravenously ate the "sine wave" worms (I believe they're some type of benign nematode), as Rich calls them ( :lol: ). Slurped them up like spaghetti. But I saw them curiously "nip" at the planaria and leave them alone. I was sure that they got munched by guppies in my other tanks, but maybe I was wrong. Or maybe they'll eat the really tiny "baby" planaria but not bigger ones. 

Anyway, I'll keep those guppies hungry for now and see if their will to survive doesn't eventually work to my benefit :twisted: . I don't actually have any shrimp in this tank, so it's not really a problem. I'm squeamish, though, and would really like the planaria gone. 

-Naomi


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## Piscesgirl (Feb 25, 2004)

Yep, the planaria is on the tail.


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## richy (Nov 8, 2004)

Piscesgirl--

the thing on the tail looks more to me like a fish louse than anything else, not planaria. are planaria worms? can anyone clarify. this seems to be a major gray area on what the true definition of planaria is. maybe it's just semantics or maybe i'm just the one that's confused.

rich


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## gnome (Jan 27, 2004)

Rich, 

Planaria are more commonly known as "flatworms." You can google up images using either of these terms or "platyhelminthes." They actually have "eyespots." If you cut one of these guys down the middle (lengthwise), each half will re-grow the "missing" half. If one flatworm eats another flatworm, the "information" stored in the eaten worm's "nervous system" will actually be acquired by the worm that ate it. They're pretty interesting creatures, but they're definitely not welcome in my home aquarium. 

-Naomi


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## richy (Nov 8, 2004)

ok that settles that. i keep thinking of the sine-wave worms, which have been called planaria as well. i will start calling the white worms nematodes, cuz it sounds like that's the distinction. =) forgive le ignorance...


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## shalu (Oct 1, 2004)

richy said:


> i keep thinking of the sine-wave worms, which have been called planaria as well.


me too........


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## Jane in Upton (Aug 10, 2005)

Hi,

so has anyone come across any more information since this thread? I read the linked article, but have not been able to find any other information about any toxin excreted by planaria that might affect shrimp.

This was an interesting thread, but I've not been able to find any further information. Any folllowups, folks?

Thanks!
-Jane


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## dhavoc (Mar 17, 2006)

most shrimp only tanks seem to have them to some degree. the population rises and falls depending on the amount of food available. most of the guys in asia dont think they are anything more than a nuisance and an eyesore, and so far i tend to agree. i have them in my CRS tank and they move way too slow to really be a threat to anything unless its already on its way out. i have yet to find one eating any of the dead shrimp that i take out yet either. they can get pretty big though, a couple got to over half an inch and kind of reminded me of garden slugs. they do secrete a slime that sticks to everything if poked or proded, but dont know if its toxic or anything. again none of the adult or babies i have seen seem to be bothered by them. some guys use dewormer medicines to get rid of them, but i am a little hesitant to try that yet.


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## Shrimp&Snails (Mar 27, 2006)

My two shrimp tanks don't have planaria....quite a few cyclops but no wormy things.

I did have a problem with planaria in an apple snail tank that I was overfeeding. I cut down the feeding and got gravel vaccing/did partial water changes which sorted things out.


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## bigtroutz (Nov 17, 2006)

A problem you may be having has to do with the number of species called 'planaria'. There are lots and all will have different characteristics, feeding behaviors and adaptations.

IF you have a species that is predatory and reaches an large enough size, it will likely feed on shrimp or their offspring. Some species employ toxins to subdue prey.

more here: Turbellaria: Definition and Much More from Answers.com


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