Microscopy Thread

1790375817979.png

@revhtree HOW COOL IS THAT?!
I didn't know you guys were promoting threads in this way now?! 😍
Wow, you're on the front page EnterName!
 
All the weird things

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By now, this thread has accumulated quite a few posts showing specimens that were never properly identified. Here is a quick overview of them, along with a few that never made it into a post. Maybe someone recognizes one of them, or has at least seen them in their own tank:


(Post 224)


2026-09-22 23-19-10 (C,S1).jpg

(No post - Egg?)



(No post - Egg?)



(Post 125 - Some kind of hydroid, but which one?)



(Post 39)



(Post 39)


NDino.jpg

(No post)


(No post, chrysophytes and some diatoms?)



(No post, chrysophytes among some diatoms?)



(Post 223)



(Post 149 - A ciliate, but which one?)

Unknown.jpg

(Post 94 - Possibly some kind of fungus/mold)


(Post 218 - A dinoflagellate, but which one?)


(No post, another dinoflagellate?)
​
 
Found this little critter in the water column, collected with a 25 micron sieve. Is it a rotifer? 400X.


 
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Then there was this thing, also seen here at 400X. About the same size as an ostreopsis dinoflagellate. No idea what it is, looks like something you'd see on a Grateful Dead t-shirt!

unknown stealie.JPG
 
@RobertK the first one should actually be a rotifer like you said. The last one looks like an oversized fungi spore. Really interesting...
 
Found another rotifer, this one is different than the one I posted yesterday. I think this one is from genus Colurella (C. adriatica?) and the one from yesterday I think is genus Brachionus.


 
1790375817979.png

@revhtree HOW COOL IS THAT?!
I didn't know you guys were promoting threads in this way now?! 😍

Well deserved recognition! What’s next, your own forum???
Thank you Dan 🤗
Maybe in 10 to 20 years, once I've finally gathered some experience 😂

I hope more people get into microscopy a little bit, not for diagnostic purposes, just for the fun of it, so we can compare and identify our findings together as a community. @RobertK, @christinna77, and a few others have already made some really cool contributions here and have added a lot of value to this thread.

I think there is a lot of potential. Diatoms, for example, are sometimes used to evaluate water quality. From playing around with nutrient levels in my tank, I can say that the ratio between cells of different genera changes visibly depending on those levels. Certain diatoms also seem to correlate with the appearance and disappearance of certain dinoflagellates in my tank, and their chloroplast density and shape sometimes changes as well. It would be great if other members could test this, too, as I don't think I will be able to set up conclusive experiments regarding this on my own.
 
Thank you Dan 🤗
Maybe in 10 to 20 years, once I've finally gathered some experience 😂

I hope more people get into microscopy a little bit, not for diagnostic purposes, just for the fun of it, so we can compare and identify our findings together as a community. @RobertK, @christinna77, and a few others have already made some really cool contributions here and have added a lot of value to this thread.

I think there is a lot of potential. Diatoms, for example, are sometimes used to evaluate water quality. From playing around with nutrient levels in my tank, I can say that the ratio between cells of different genera changes visibly depending on those levels. Certain diatoms also seem to correlate with the appearance and disappearance of certain dinoflagellates in my tank, and their chloroplast density and shape sometimes changes as well. It would be great if other members could test this, too, as I don't think I will be able to set up conclusive experiments regarding this on my own.
I have observed the chloroplast change in diatoms in population that were declining. Not only that, but I observed microscopic “oil droplets”, the color of which was the same as the inside of the diatoms. To confirm that the oil droplets were diatom derived, I used a coverslip to smash the diatoms in a sample with no oil droplers and produced a massive amount. I have seen oil droplets in the past but never investigated them until now. I assume the appearance of these droplets correspond to dying diatoms.
 
Thank you Dan 🤗
Maybe in 10 to 20 years, once I've finally gathered some experience 😂

I hope more people get into microscopy a little bit, not for diagnostic purposes, just for the fun of it, so we can compare and identify our findings together as a community. @RobertK, @christinna77, and a few others have already made some really cool contributions here and have added a lot of value to this thread.

I think there is a lot of potential. Diatoms, for example, are sometimes used to evaluate water quality. From playing around with nutrient levels in my tank, I can say that the ratio between cells of different genera changes visibly depending on those levels. Certain diatoms also seem to correlate with the appearance and disappearance of certain dinoflagellates in my tank, and their chloroplast density and shape sometimes changes as well. It would be great if other members could test this, too, as I don't think I will be able to set up conclusive experiments regarding this on my own.
I have observed the chloroplast change in diatoms in population that were declining. Not only that, but I observed microscopic “oil droplets”, the color of which was the same as the inside of the diatoms. To confirm that the oil droplets were diatom derived, I used a coverslip to smash the diatoms in a sample with no oil droplers and produced a massive amount. I have seen oil droplets in the past but never investigated them until now. I assume the appearance of these droplets correspond to dying diatoms.
The chloroplast density seems to change as well as the color sometimes. But as I have never gotten below 300μg/L Si in my tank, I think I have never really seen a large scale diatom die-off just a transition between species. I will try squashing some diatoms later to see what you are talking about 😅
2026-09-25 16-19-44 (B,R1,S1).jpg
Do you mean those "oil droplets"?
 
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The chloroplast density seems to change as well as the color sometimes. But as I have never gotten below 300μg/L Si in my tank, I think I have never really seen a large scale diatom die-off just a transition between species. I will try squashing some diatoms later to see what you are talking about 😅
2026-09-25 16-19-44 (B,R1,S1).jpg
Do you mean those "oil droplets"?
Yes, but even to the point of filling the entire cell. Outside the cells the oil droplets ranged in size, suggesting that they might be coalescing. My poor diatoms were clearly stressed :-)
 
Yes, but even to the point of filling the entire cell. Outside the cells the oil droplets ranged in size, suggesting that they might be coalescing. My poor diatoms were clearly stressed :-)
SquashedDiatoms.jpg
Didn't work out the way I expected, I want my money back Dan! 😁 Looks like normal, "solid", Diatom contents... not liquid/oily and coalescing.

To be fair, the species-balance has shifted again so most of the diatoms weren't the "bubble"-containing Licmophora species anymore and I'm back to these guys instead:
2026-09-28 18-23-26 (C,S1).jpg
But I cropped around two species that do contain these blobs/flakes and they don't seem to merge. I assume diatoms are thriving too much in my tank right now.
 
SquashedDiatoms.jpg
Didn't work out the way I expected, I want my money back Dan! 😁 Looks like normal, "solid", Diatom contents... not liquid/oily and coalescing.

To be fair, the species-balance has shifted again so most of the diatoms weren't the "bubble"-containing Licmophora species anymore and I'm back to these guys instead:
2026-09-28 18-23-26 (C,S1).jpg
But I cropped around two species that do contain these blobs/flakes and they don't seem to merge. I assume diatoms are thriving too much in my tank right now.
No money back guarentee!

I had pinnate diatoms (shouldn’t matter) as pictured above and imagine the cell almost completely filled with a clear blue-green substance rather than the textured golden filling. Weird, right? I assume serious health issues, being expressed as high lipid levels containing dissolved chlorophyll. My diatoms had been growing under nitrogen depleted condition for many weeks with plenty of silicate. As I said above, I have seen this before and had assumed the perfectly clear, blue-green spheres were some sort of algae. Probably a source for diesel fuel.
 

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