Does this look like hydra to you?

[rebe]

I'm a bit concerned because it's popped up suddenly in my 5 gallon with the beckford pencilfish fry

 

[Colin_T]

No. It looks more like a bryozoan, which are harmless and rare in aquariums so look after it

 

[Seisage]

Hmm... I'm not as familiar with freshwater inverts as I am with saltwater ones, but this doesn't look like a hydra to me. Hydra are cnidarians with polyp-like or anemone-like bodies. They generally have smooth tentacles that are arranged in a circle and all lead to a central mouth on a stalk. This thing has a very thin "stalk" with no centrally located mouth.

I think this is a different hydrozoan—a colonial one. It'd be somewhat related to hydra, but it's a very different organism. Each of those little translucent blobs is a distinct individual, and they're all connected in a colony. To me, it looks similar to Obelia. The genus has some freshwater representatives apparently, but I don't know anything about those ones, so I can't say for sure if yours is a freshwater Obelia.

I'm also not sure whether they'd be harmful to the fry. How large is this animal you've found? If it's smaller than a fry, I personally wouldn't worry.

I'd say it could look like a bryozoan, but the "stalks" of bryozoans that grow upright are also made up of individuals (so it's like a skyscraper made of neighbors) whereas the "stalks" of this thing just look like thin threads. Bryozoans have exoskeletons that are usually more robust too.

Again, this is mostly a marine perspective. I'm not as familiar with freshwater groups

Edit: here's a freshwater bryozoan in an aquarium for reference. You can see the little tentacle feeding structures extend all the way down the "stalk". Each set of tentacles belongs to a different individual. Unfortunately, there aren't many good photos of freshwater colonial hydrozoans to compare it with.

 

[rebe]

I'm also not sure whether they'd be harmful to the fry. How large is this animal you've found?

They're very small, so far anyways. 2mm maybe, if you measured from top to bottom. That's with the largest ones, there are others far smaller.
I'm going to get a little microscope-camera from Amazon, that I can use to study them. I'd like to see their features better, especially to compare them to suggestions you've made. Hopefully to identify them. If they're so rare, it would be fun to do a little study on them

 

[rebe]

Forgot to add these two images. So far they are small compared to the fry

 

[Seisage]

They're very small, so far anyways. 2mm maybe, if you measured from top to bottom. That's with the largest ones, there are others far smaller.
I'm going to get a little microscope-camera from Amazon, that I can use to study them. I'd like to see their features better, especially to compare them to suggestions you've made. Hopefully to identify them. If they're so rare, it would be fun to do a little study on them

This would be great! If you can get an image at a higher magnification under a scope, I'd probably be able to give you an answer/educated guess with much more confidence

 

[rebe]

This would be great! If you can get an image at a higher magnification under a scope, I'd probably be able to give you an answer/educated guess with much more confidence

That would be great for me! I'll order that today, so it should arrive before the weekend. I'm excited to use it to look at all the microscopic aquarium life

The majority of the pictures I have were taken with a x30 magnification lens clipped to my phone, and if this equipment works then I should be able to go up to x1000 magnification

 

[Seisage]

That would be great for me! I'll order that today, so it should arrive before the weekend. I'm excited to use it to look at all the microscopic aquarium life

The majority of the pictures I have were taken with a x30 magnification lens clipped to my phone, and if this equipment works then I should be able to go up to x1000 magnification

Yes, that'll be fantastic! Microscopes of any sort are super fun and useful. When I eventually move away from the marine station I work at, I'll have to get a microscope of my own. A professional compound or dissecting scope is best, but even the little camera ones are really useful, and they're nearly on par with dissecting microscopes anyway. Depending on the case, you may even be able to use it to diagnose some diseases that you couldn't ordinarily see with a naked eye.

 

[GaryE]

When digital microscopes were new and unsophisticated, we had one at our High School. While I was an English teacher, I was already a far gone fish nerd, and I brought in some eggs from the fish in my avatar, an Aphyosemion exigoideum killifish. Aphyosemion eggs are perfectly transparent, and take around two weeks to develop. A few of the 16 year olds became very excited, as they could do daily films of the development inside the egg. They even got video of red corpuscles going through the heart. It was a really good school project, and you don't need to still go to school to try things like that.

The colonies you have their don't resemble predators to me. I've had them once or twice in tanks, and no harm was done. Plus they are extremely beautiful.

 

[MattW3344]

I get these all the time popping up. My first tank was full of them never had any issues

 

[Colin_T]

I get these all the time popping up. My first tank was full of them never had any issues

seems to be a UK thing because we don't get them here in Aust.

 

[GaryE]

seems to be a UK thing because we don't get them here in Aust.

If they aren't in Australia, then they probably won't kill anything.

 

[AdoraBelle Dearheart]

They are quite beautiful! The first images made me think of a crystal chandelier, or snow frosted trees.

I haven't seen them before myself, but my glasses are also really old and I need new lenses, but I'll be looking for them here now, and follow the thread with interest for the microscope images! TY for posting something new and interesting, and investing in some kit for a home science project

 

[Back in the fold]

There’s something you don’t see everyday .

 

[rebe]

The colonies you have their don't resemble predators to me.

That's very good to hear! I've been keeping a close eye on that tank, and I haven't seen any fry or critters stuck on them.

I get these all the time popping up. My first tank was full of them never had any issues

Fantastic! There seems to be very little information about them online, when it comes to my fish, I have a habit of fearing the worst and researching every possible reason/answer. Not a bad thing to be cautious but I could probably relax a little
Good to see the pictures of them in your tank too!

and follow the thread with interest for the microscope images! TY for posting something new and interesting, and investing in some kit for a home science project

I'm excited to see the microscope camera and images I might be able to take. I'll definitely be sharing loads of pictures when it arrives