Help identifying what I found in my aquarium please

[Mormegil]

Hi,

All my fish died recently in my 10 gallon. So I figured I'd throw a water sample under the microscope and see if I could find the culprit. I found a lot of interesting things - including about a million rotifers (total in 10 gallons).

Can someone help me ID these guys? The scale bar is 50 micrometers and everything here is under phase contrast lighting.

I'm pretty new at this, so please bear with me. I just used the scope at lab, where we're usually looking at mammalian cells in tissue culture plates - they don't move, so this was pretty cool.


That's a rotifer on the right, but what's that on the left? You can't see it too well, but it has two hooks on the left (one is folded up). I'm wondering if it's a fluke larva (Dactylgyrus), or is this too small?


full size http://farm1.static.flickr.com/149/3696 ... 9e08_o.jpg
These are shots of different specimens. They moved "flatly" - unlike the twirling of paramecium (which I also found). I didn't see any green, so I assume no chloroplasts.


full size http://farm1.static.flickr.com/149/3696 ... d6cd_b.jpg
These are multiple shots of one specimen. It seemed to be anchored to the coverslip or slide at the "foot." Is this a different kind of rotifer, or a fluke larva? When it's mouth opened, it looks liked cillia beating (but I don't know if a fluke's teeth do a similar action).

Thanks for any help.


P.S. It's possible the parasite that killed my fish isn't in these samples, are there was a smaller darting cilliate that I couldn't get on film (or sensor). Plus this was a couple of days after treating my tank with copper sulfate to kill Ich (Ichthyophthirius multifiliis) or Velvet (Oödinium).

[Ken Ramos]

I don't know a whole lot about aquariums or fish, there are some on here though who know a great deal. I would suspect a fungal pathogen may have killed your fish. Inspect the gills of them and if possible make a smear from the gill area of some that have died. I would suspect also that you will find the etiological agent there.

Your photographs on the other hand are quite good. You seem to have a gastrotrich in the first, nuzzling a rotifer and a number of Hypotrichia in the second and lastly rotifers.

Yes, I would take a closer look at the gills of those fish. Your culprit is probably there.

[bernhardinho]

Hi,

those pics are beautiful, please more!!!

Ken already told you the most important things. Your last rotifer is probably a Rotaria (bdelloid). The hypotrich Ciliates could be Euplotes.

Bernhard

[Mormegil]

Thanks for the info and the compliments. I took a lot of photos, most had motion blur or weren't properly focused.

Part of the problem I'm use to an SLR, and I had to use the compact digital camera attached to our scope. That's not an issue when I'm taking pics of epethlial cells, since there's no movement. But trying to capture these guys are something else.

Quick question, does closing down aperture have any appreciable effect on depth of field, like with regular photography?

Oh, here's pics from the first batch - mainly rotifers.

[beetleman]

I would agree that these look like common critters you would find in any aquarium. If all your fish died in a short time, you may have had something go wrong with your water chemistry. Ich and velvet you can see on the fish and they do not kill very rapidly. Copper is very toxic to living things and if not dispensed correctly could kill the fish very fast.

[rjlittlefield]

Mormegil,

Goodness gracious, your first two posts here, you got replies from two other administrators, and no one has yet welcomed you to the forums! Let me fix that.

WELCOME ABOARD!!

I agree with the other guys -- your pictures are very nicely done, and the things in them look like normal waterlife, not pathogenic.

Protozoa are notoriously difficult to photograph well posed, in focus, and not motion-blurred. Flash solves the motion blur problem, nothing much helps with focus, and posing is a matter of luck. But the bugs sure are fun to watch, aren't they?

Your question about aperture has a three-part answer. Part one: The camera aperture has no effect assuming that its lens is well matched to the scope. Part 2: There is an "aperture diaphragm" built into the scope's illumination system. Closing that down will give you more depth of field and more contrast. But... Part 3: Closing down the aperture diaphragm very much will also cut into your resolution due to diffraction effects. You can evaluate that tradeoff by looking through the eyepieces.

It's an unfortunate fact of life that DOF through a light microscope is very shallow. The table at Nikon's MicroscopyU shows DOF around 1-5 microns at the magnifications you're using. As thick as these bugs are, there's just no way that you're going to get more than a thin slice sharp at one time.

One more thing, please check the posting guidelines -- there's a limit of 3 images per day per forum, and 800 pixels on the longest side. No problem with the ones here -- it's a common mistake getting started.

Again, welcome aboard! We're looking forward to seeing more pictures.

--Rik

[Mormegil]

Thanks for the welcome, and sorry about going over on the image size. I thought it was 800 pixels at the widest - to not mess up the window.


I guess I'm pretty spoiled working in a lab*. Those shots were taken on an Olympus Inverted Fluorescent Microscope. Though, you can see I wasn't using fluoresence. Maybe I should put up some of my Green Fluorescent Protein labeled cells.

The lab upstairs has got a confocal microscope - and depth of field isn't a problem there, as you can stack the images as the focal plane is automatically adjusted. That's a nice scope.

The most expensive / nicest scope I've seen, but didn't get to play with was a dual photon confocal microscope - where the visible light is created (by a quantum mechanical effect) at the focal plane by the intersection of a pair of lasers - cutting down on blur and I believe allowing the use of thicker specimens.


* for instance, I just took 50ml of my aquarium water in a conical tube, and used a tabletop centrifuge to pellet whatever was in there, so I could pull off about 49ml - so I concentrated my sample 50 fold. That made it a lot easier to find specimens.


Anyways, this isn't my usual photographic forte. I've got a few "macro" images, using extension tubes, but nothing like the ones I've seen in these galleries. Amazing stuff.

Funny thing is my most popular "macro" image on Flickr isn't even a macro image, it was just a huge dragonfly (taken with a 70-200mm lens).

[Mormegil]

Oh, just to clarify, I didn't add copper sulfate until after all but one fish had died*. That last one was already on it's way out.

I didn't get these shots until a couple of days after the addition of copper sulfate. I also cranked up the temp to speed up the life cycle of the parasites to clear them out of the aquarium faster. So I guess it's not too suprising I didn't find any of the parasites.



*First the newst fish died, then the other 2 of it's species went, then the reast - so I'm pretty sure it was a communicable disease / parasite of some sort.

[MacroLuv]

Welcome Mormegil!
Very nice images.
I want more dragonfly macros but in the Macro and Close-up Photography Gallery please.

[Charles Krebs]

Welcome Mormegil...

Great phase shots you started with... hope to see many more.

It seemed to be anchored to the coverslip or slide at the "foot." Is this a different kind of rotifer, or a fluke larva?

As Bernhard replied, it is a Bdelloid rotifer. They anchor their tail end when feeding (with corona of cilia) and often move about ("inchworm" like) by alternating anchoring the tail end and head end. When they move like that they could be mistaken for a variety of creatures. In fact, the term "bdelloid" come from the Greek bdella..."leech".

[beetleman]

Yes Mormegil, welcome aboard. My Apologies on not welcoming you to the forums...I must have been "ZONED IN" on your wonderful pictures. and I didn`t notice the post numbers . I would love to have all those toys to play with.....would make me want to stay at work late

[svalley]

Mormegil, Welcome! Very nice images!

[gpmatthews]

Yes, good pics, and welcome. Looking forward to more...