What looks like hydra, but has many more appendages and acts like a barnacle?

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knifegill

knifegill

Peacock Bass
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Sep 19, 2005
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The snail I collected from a nearby pond and just added to my 55 has several little hitch-hikers. They are stiff, bushy and I swear I saw one snap shut for a moment like a barnacle. Too many arm/legs for hydra, and they're maybe 1/16th of an inch tall. Anchored by a single filament, difficult to make more out with my magnifying glass. They're white, and look a little like fungus until closer inspection.
Any ideas?
 
I thought I was the only one this had happened to! I had an assassin snail turn up from abroad covered with these things, so much so that he looked like he was covered in a fungus (all his companions were clear). They look like miniature bristle worms, just visible to the naked eye, and like bristle worms the tentacles retract into the body tube when touched, but then whole tube also retracts to a bud.

I believe they must be a type of hydra, although I agree, they look as though they have too many tentacles for this. Mine have been there a while and they do not seem to have done any harm to either the snail or any of his tankmates.
 
Do they look like this? Not a very good pic but sounds like the same thing I have, all over my tank glass and I was worried it's something harmful but it almost has to be a hydra. I was about to post them when I noticed your thread. As many as I have they HAVE to be coming out of my tapwater. I thought the same thing though, too many tentacles, never seen a hydra with that many.
They're in my discus tank so it's quite worrysome to me. Not in any of my other tanks and that's the only tank I do daily water changes on.

Biggest ones are maybe a millimeter long. The little white dots all over the glass are the same thing just much smaller.
Look kind of like baby pest anemones from a saltwater tank (aiptasia).

whatisit.jpg

whatisit2.jpg
 
Some common Hydra species, such as H. oligactis, have numerous long tentacles. If the tentacles are very short, it could possibly be a bryozoan, a sessile rotifer, or even a freshwater jellyfish polyp.
 
Mine have many more tentacles than any I'm seeing on google including H. Oligactis. They're a lot like a fanworm or featherduster (I think that's what Anna Robinson meant to say instead of bristleworm, since bristleworms look more like a normal worm, correct me if I'm wrong).
I had little featherdusters that grew on the underside of my liverock and these things look almost exactly the same.

(BTW, sorry if I'm threadjacking, it just sounds like the exact same organism, hopefully I'm correct)
 
Hrrm. That sounds vaguely like a sessile rotifer. I have some pics on Photobucket, but the site seems to be down now. I'll try to find some elsewhere.

*EDIT* Here: http://images.google.com/imgres?imgurl=http://www.microscopy-uk.org.uk/mag/imgnov00/collo2b.jpg&imgrefurl=http://www.microscopy-uk.org.uk/mag/artnov00/mouse.html&usg=__lgSI1PuCsAB14KLVaiyNcTYz2vQ=&h=400&w=263&sz=21&hl=en&start=3&tbnid=jkhHU6g0Z9gH9M:&tbnh=124&tbnw=82&prev=/images%3Fq%3Dsessile%2Brotifer%26gbv%3D2%26hl%3Den%26safe%3Doff

The ones I have run across are much like you describe, smaller than hydra, and contract into a little barrel-shape when disturbed. You can just barely see their lophophores moving; more an impression of motion than actually seeing individual structures.
 
Hmmm, the description of their behavior matches but these seem much too big. Biggest are a couple of mm long.

I wish I still had a microscope to look at them under.

If that is what they are I guess they're beneficial since they're supposed to clean water.
 
i dont think theyre rotifers, theyd be too small for you to see like that.
 
i have what seems to be the same thing. i bought a longnose gar who seemed healthy, but now i have little hydra looking things all over my tank. i assume they came in off the gar. i did a salt treatment today so ill let you know how that goes.(i go old school, to scared of chemicals right now). ill take some pics and post them asap
 
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