Mystery Creatures

This video is posted on behalf of a club member that has lots of little white cyst like things attached to stones in his tank.

I videoed the cysts under a microscope and also tried to remove them whole from the stone they were supplied on, however, they are extremely hard and limpid like I could only remove the top part leaving the base in contact with the rock, using a razor blade. Inside each cyst like structure were between 4 and 8 little creatures buzzing around. The cysts are approx 1 - 1.5mm diameter, that gives you an idea of the size of the creatures inside.

Anyone any idea what these are and if they are harmful to fish?





Darag

hi darragh
Did these creatures come into the aquarium on the rocks ...? or did they appear on the rocks in the tank

Lar

Lar

I don't know, they aren't in my tank, thankfully. Their owner did collect rocks from different places so it is possible that's how they came in, from what I can gathered the numbers have been increasing but not noticeable impact on the fish, that he is sure of.


Daragh

Great video. Very clear. You will have to show me how to capture images or video that clear on the microscope.

I have never seen these before and did a search but came up with nothing that matched.

Snails. Ferrissia wautieri. I have them as well. In short while they covered stones and boogwood . botias are fighting with it, but is hard because of small size and hard shell. it looks like that they making holes in stones if are long time enough in one place.

the original photo looks just like the white snail eggs i have found all over my tank too .

those white stuff they are snails. just few mm in size.

I took the Vid to DCU Biology lab, they will check it out but say it isn't a snail mass, more like Protozans, they will get back to me.

Kev.

At first look, I thought they were snail eggs too, but they were too hard and also I would not expect more than organism in each case.

I will be very interested to hear what UCD say.


Daragh

I dont think they are wautieri. You could remove them with your finger nail. The shape of the shell seem wrong as well.
Also inside would be a snail unless the snail was a host for the Protozoan. Which is quite possible.

very interesting video daragh. i will be interested to know what they are. they are obviously very tiny judging by the magnification.

Ok, Here's the reply from Trinity College Dublin..

Dear Kevin

You have thrown up a real problem here! I've been through all the animal phyla that I'm familiar with, and can't make a perfect match. I agree with you that it's not necessarily a parasite, so perhaps the owner (Daragh Owens?) followed the little critters and saw what they grew into?

So, I have to go back to more questions.

What is the scale of the video? Is the white, shiny cyst a few mm across, or bigger (a centimetre or more)?

The cyst is on a rock, not on a fish, so that would rule out some parasitic forms. There are elongated, worm-shaped structures on the rock - could these be the remnants of the organism which produced the cysts?

There are perhaps 20 ciliated swimming organisms inside the cysts; each might be 100-200 microns in length? again I can only guess at the scale. The 'head end' has what appears to be 2 groups of cilia, which propel it, and may sweep food particles into a gut. It is reminiscent of a rotifer (these look like a swimming electric razor!). There is also something in the mid-line or further back, which might be a gut rudiment.

They could be PROTOZOANS - single-celled organisms like Paramecium or Vorticella. But I don't know enough about them, including how they would get into or start off in a cyst.

Here is a summary of possible INVERTEBRATE groups:

PLATYHELMINTHES [Flatworms] – (Like a liver fluke cercaria emerging from a snail). But I don't know of any flatworms that produce cysts like that.

BLASTOCOELOMATES – This bizarre group of small creatures is a possible, especially Rotifers or Gastrotrichs, but individual offspring are produced in the ones I know of.

ANNELIDA (worms) - Some marine worms release swimming ciliated 'Trochophore' larvae. The earthworms and freshwater worms (Oligochaetes) and Leeches (Hirudinea) both produce a cocoon, containing up to 20 eggs. But I don't know any that produce free-swimming, ciliated larvae.

ARTHROPODA - nothing matches here.

MOLLUSCA – Some, chiefly marine snails, produce egg capsules. Snails may produce ciliated 'Trochophore' larvae (like those in annelids), which may metamorphose into 'Veliger' larvae.

LOPHOPHORATES – A mostly marine group, but some ECTOPROCTS (Bryozoans) are freshwater, and some are poly-embryonic, the larva becoming cyst-like and releasing many ciliated larvae. The worm-like structures on the rock might be the remnants of a bryozoan's horny skeleton. [The rock might also be marine in origin, and then the elongated structures could be anything!].

If I had to make a single choice, it would be a Bryozoan. But I've only looked at the resting eggs released by Irish freshwater ones (like Cristatella and Plumatella) and I know very little about their early development. And I wouldn't rule out a parasite, if the evidence pointed that way.

Maybe your colleague can provide some more answers, and we might get to the bottom of this?

All the best
Julian

--
Julian Reynolds PhD, Emeritus Fellow TCD
115 Weirview Drive, Stillorgan, Co. Dublin, IRELAND
Tel. +353 1 2887856
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Cheers John.

I did a bit of further investigation and I think this is closer to the truth given it's reproduction etc.


Argyrotheca cistellula


Kev.

Isn't Argyrotheca cistellula marine?

Thanks for getting such detailed information, I will try and get better measurements and footage of the litttle creatures over the next couple of days, I can't do it tonight as I am off to Aslan


Daragh

Daragh
Is it possible some of these rocks were collected from the sea shore...?

Lar

PS - Kev... Well done on following this up

PPS - Daragh ....Enjoy Aslan.....

Lar

Sure it takes your mind of the other crap goin' on in the world.

Kev.

i have to say i find this both interesting and disturbing it is a perfect example of the folly one faces when adding items to your set up! this could be both dangerous to your fish but more importantly Family members

I hope this tank is been treat as a quarantine tank!

if this was mine i would remove all items they are attached to and either destroy or boil for a few hours.

but here i would also remove some and if Kev was agreeable to have some brought to Trinity to be examined. so any treatment if required can be id or get advice on actions required.

i am sorry this is such a negative post but sometimes our inquisitive nature stops us acting responsibly. and hope fully i am over reacting

Mickey

Ps. sorry about spelling

gotta say this is a very interesting and in depth thread ....... congrats to all involved

Yep Mickey, no probs, the guy involved in the ID would love to have a closer look.

087 997 5849

I'll bring them to him if they are still available.

Kev.

Very interesting thread, would also be interested to know where the owner sourced his rocks as they may well have come from the source of the rocks initially.
Great info on the thread lads. Super effort.
Gavin

Update:

Very simple explanation after all, they are the eggs (or egg cases) of nerite snails, apologies I think someone suggested that already - but what seemed to make that unlikely was that there were more than one lavae (or whatever) in each egg cases which seemed to point away from snails.

Anyway thanks to Stertnik, I saw them in his tank recently and they are exactly the same. So nothing nasty and nothing to worry about, they won't hatch and survive in freshwater, so no need to worry about a snail population explosion either.



Daragh

great read, really enjoyed this

Thanks to Daragh and all the inspector Cluseauxs helpers in this long drawn out tale. Now I can get back to my Nerites and their lost potential family. My next challenge is to rear these nerites ,Bren.