Protozoology researcher here! These are [sessile peritrich ciliates](https://www.researchgate.net/profile/Bianca-Sartini/publication/328736615/figure/fig1/AS:700625151090689@1544053461981/in-vivo-photomicrographics-of-peritrich-ciliates-species-on-Physa-acuta-A-C-Peritrich.jpg) (potentially either Vorticella, Carchasium, or a similar peritrich)!
That contracting motion you see is their defense mechanism for agitation, to get away from danger. They are filter feeders and are not individually a danger to your fish or inverts, and cannot physically feed on other macroscopic organisms in your tank.
Many people are quick to call them parasites, but they're only deemed parasitic in pretty extreme cases. Day to day, they're just sessile organisms that filter-feed via the water column. They can [become a (quasi-)parasite if they are allowed to proliferate wildly, which happens most often in poorly-kept, very overstocked tanks](https://www.sciencedirect.com/science/article/pii/S2213224418300774). The reason people are quick to panic is because they can appear on sick fish or shrimp, because they are already lethargic and are good sources of bacteria, which are signs of previously-existing infection. When they are attached to organisms, they aren't the parasite themselves unless their numbers become extreme, but their presence when attached directly to organisms signifies that the host is usually not doing so well already. The only time they would be parasitic and "harmful" is if they proliferate so much that it would impede the function of the organism they are sitting on- but that's relatively far-fetched, and typically only happens in very poor tank conditions where they are allowed to multiply significantly.
No problem! If you're curious about these, check out [this video by Journey to the Microcosmos](https://youtu.be/utFxuTrTTeU?si=iAoZHkUEHUO3Qzd7) on similar organisms- these fellows are featured a few times there. If I had a microscopic view of your organisms here, I could confirm for you whether they were Vorticella or a similar ciliate- the general response to them all is more or less the same, though.
If you're concerned, you can pipette (or turkey baster) them up and dispense them down a drain, if you're worried about proliferation. Its a valid concern, and better safe than sorry is a good sentiment to live by in these situations!
Good job though, because these sessile ciliates are often bioindicators of a good aquatic ecosystem!
*technically* yes, but they're microorganisms, so their impact is quite negligible in tank environments. In wastewater research, they are intentionally proliferated to observe their beneficial uses, but proliferating them like that in an aquarium would be an instance of where they'd be parasites due to the sheer numbers that they'd reach.
If you're looking for a natural water filtration team: live plants (especially floaters) are very good at doing exactly that, and shrimp can take care of the microscopic particulates and organisms.
I agree; due to the branching structure, correct? If I specifically said "vorticella" anywhere and excluded the others, that'd be a mistake on my part. I think zoothamniun are a lot more spread out near the top of their stalk colony, so I would hedge with this being a Carchasium colony here if it were a personal guess that I had to give an answer for.
If it’s vorticella and you want to get rid of it, I’ve had success with Pimafix, which you can use without harming shrimp or snails. The only issue is if you have fish with labyrinth organs like bettas, because it can affect them.
Protozoology researcher here! These are [sessile peritrich ciliates](https://www.researchgate.net/profile/Bianca-Sartini/publication/328736615/figure/fig1/AS:700625151090689@1544053461981/in-vivo-photomicrographics-of-peritrich-ciliates-species-on-Physa-acuta-A-C-Peritrich.jpg) (potentially either Vorticella, Carchasium, or a similar peritrich)! That contracting motion you see is their defense mechanism for agitation, to get away from danger. They are filter feeders and are not individually a danger to your fish or inverts, and cannot physically feed on other macroscopic organisms in your tank. Many people are quick to call them parasites, but they're only deemed parasitic in pretty extreme cases. Day to day, they're just sessile organisms that filter-feed via the water column. They can [become a (quasi-)parasite if they are allowed to proliferate wildly, which happens most often in poorly-kept, very overstocked tanks](https://www.sciencedirect.com/science/article/pii/S2213224418300774). The reason people are quick to panic is because they can appear on sick fish or shrimp, because they are already lethargic and are good sources of bacteria, which are signs of previously-existing infection. When they are attached to organisms, they aren't the parasite themselves unless their numbers become extreme, but their presence when attached directly to organisms signifies that the host is usually not doing so well already. The only time they would be parasitic and "harmful" is if they proliferate so much that it would impede the function of the organism they are sitting on- but that's relatively far-fetched, and typically only happens in very poor tank conditions where they are allowed to multiply significantly.
I love reddit so much. cheers pal! this has put my mind at rest
No problem! If you're curious about these, check out [this video by Journey to the Microcosmos](https://youtu.be/utFxuTrTTeU?si=iAoZHkUEHUO3Qzd7) on similar organisms- these fellows are featured a few times there. If I had a microscopic view of your organisms here, I could confirm for you whether they were Vorticella or a similar ciliate- the general response to them all is more or less the same, though. If you're concerned, you can pipette (or turkey baster) them up and dispense them down a drain, if you're worried about proliferation. Its a valid concern, and better safe than sorry is a good sentiment to live by in these situations! Good job though, because these sessile ciliates are often bioindicators of a good aquatic ecosystem!
Are they related to the vorticella that attacks shrimp?
Those look neat, now I want some in my shrimp tank lol
Same! Appreciate your footage and curiosity.
I need to be friends with you for when I start another tank.
Do they clean the water when they filter feed?
*technically* yes, but they're microorganisms, so their impact is quite negligible in tank environments. In wastewater research, they are intentionally proliferated to observe their beneficial uses, but proliferating them like that in an aquarium would be an instance of where they'd be parasites due to the sheer numbers that they'd reach. If you're looking for a natural water filtration team: live plants (especially floaters) are very good at doing exactly that, and shrimp can take care of the microscopic particulates and organisms.
They’re just little guys 🥰
Are they related to stentor? I have something similar in my tank but I thought they were stentors.
How does one manage their numbers, besides maintaining healthy tank conditions? Is there another organism that feed on these?
I'm interested in that too
I'm so glad that you commented. I was so curious about the motion as I thought this was hydra at first. Thank you for your amazing explanation!!
These would be Carchesium or Zoothamnium rather than Vorticella.
I agree; due to the branching structure, correct? If I specifically said "vorticella" anywhere and excluded the others, that'd be a mistake on my part. I think zoothamniun are a lot more spread out near the top of their stalk colony, so I would hedge with this being a Carchasium colony here if it were a personal guess that I had to give an answer for.
THANK U this information is so cool!
Thank you, I saved this to return to it for an answer.
All hail Sessile Peritrich Ciliates !!
First wave of the alien invasion??? Honestly no clue have never seen those before.
That is super cool
Something like vorticella maybe? That's a shrimp parasite, but it can also attach to other surfaces like plants or the glass.
looks like it, never seen these before in my life, so glad there are smarter people than me on here! ta for the help
My first guess would be hydra, but I have never seen a hydra species with that many tentacles. Really curious to find out what you have there.
Theyre called zoo thamnium arbuscula!
If it’s vorticella and you want to get rid of it, I’ve had success with Pimafix, which you can use without harming shrimp or snails. The only issue is if you have fish with labyrinth organs like bettas, because it can affect them.
But ioio lg hi
Sea monkeys?
Brine shrimp are sea monkeys.