# Critter I.D please. help me Darrell.



## Mark Evans (9 Oct 2010)

I've noticed these things for some time now, and wondered what they are. There tiny and sway in the water. I stumbled across them whilst taking pics of snail eggs.







and heres the snail eggs


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## Garuf (9 Oct 2010)

No one looks like a hydra, I had them initially in my nano but my rainbows soon saw them off.


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## Mark Evans (9 Oct 2010)

thanks garuf. mystery solved. leave them then i take it


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## BigTom (9 Oct 2010)

I wouldn't be too keen on being overrun with hydra. Theyre basically a type of jellyfish that never progresses to the adult life stage, and they'll apparantly predate juvenile fish/shrimp. This is going off internet wisdom, I've never had them myself.


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## Garuf (9 Oct 2010)

It's my understanding they take fry and the tiniest of shrimps but I never saw it. I had m. preacox and they actively hunted them out till the point even if I tried I couldn't find any.


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## Gill (9 Oct 2010)

They Do Look cool, I would love some of these just see them hunt the daphnia i have.


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## Graeme Edwards (10 Oct 2010)

I have had hydra before. 

Nothing to worry about to be fair. I think at epidemic proportions, they may cause irritation to skin or maybe fish.

As for them taking small shrimp and fish. I very much doubt that the hydra we see can take hold of anything except zooplankton like cyclops and daphnia - probably only their young. 

Have a read of this - http://en.wikipedia.org/wiki/Hydra_(genus)


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## George Farmer (10 Oct 2010)

I'm surprised you have hydra, Mark.  It's usually associated with long-term, low-maintenance set-ups!!


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## dw1305 (12 Oct 2010)

Hi all,
Lovely photo, you can really see the green symbiotic  photosynthetic algae in the "arms". As every-one has already said definitely _Hydra_. I think of them as little fresh water corals  (may-be a sales opportunity on Ebay?) - <http://cas.bellarmine.edu/tietjen/images/cnidarians.htm>. 

I tend to ignore them unless I have really tiny fry (Gourami/ Rainbow Fish sized), and if you don't feed much in the way of Daphnia or BBS they tend to decline. I was looking for some the other day, there used to be some in the lab. tanks, but since I haven't kept fish (just Shrimps) or fed live food they have declined and I couldn't find any.

cheers Darrel


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