Super tiny... hydroid?

[Michael Hughes]

It was not easy to get a shot of this little thing with my phone. The central disc, for lack of a better term, is somewhere around half a millimeter (estimate).

@EnterName have you seen something like this before?

 

[EnterName]

It's a bit too irregular for a Hydroid medusa, I suppose or can it swim away and looks like a jelly fish?
https://www.reef2reef.com/threads/microscopy-thread.1138845/post-14401843

Hydroids can create the oddest structures: https://www.reef2reef.com/threads/microscopy-thread.1138845/post-14463276
So maybe it's just the beginning of some colony

 

[Michael Hughes]

It's a bit too irregular for a Hydroid medusa, I suppose or can it swim away and looks like a jelly fish?
https://www.reef2reef.com/threads/microscopy-thread.1138845/post-14401843

Hydroids can create the oddest structures: https://www.reef2reef.com/threads/microscopy-thread.1138845/post-14463276
So maybe it's just the beginning of some colony

I haven't seem them swim to my knowledge. First noticed them in my pico tank a few months ago after adding some macroalgae, oyster shells, and hermits from the Atlantic coast of FL.

Over a few months they mostly disappeared from the acrylic. I later transferred some stuff from that tank to the 125 g. That was about a month ago, and this is the first time I've seen one on the glass here. It wasn't there yesterday though, so perhaps it could be a recently settled/attached medusa?

 

[EnterName]

It's a bit too irregular for a Hydroid medusa, I suppose or can it swim away and looks like a jelly fish?
https://www.reef2reef.com/threads/microscopy-thread.1138845/post-14401843

Hydroids can create the oddest structures: https://www.reef2reef.com/threads/microscopy-thread.1138845/post-14463276
So maybe it's just the beginning of some colony

I haven't seem them swim to my knowledge. First noticed them in my pico tank a few months ago after adding some macroalgae, oyster shells, and hermits from the Atlantic coast of FL.

Over a few months they mostly disappeared from the acrylic. I later transferred some stuff from that tank to the 125 g. That was about a month ago, and this is the first time I've seen one on the glass here. It wasn't there yesterday though, so perhaps it could be a recently settled/attached medusa?

You should be able to use a pipette to get it out and have a closer look.

These things can be really odd. I had medusoids and "digitate hydroids" (the tentacles) when the system was less than a year old. Then they disappeared completely. After I transferred the rocks, water, and livestock into a new tank (same size as the old one), they showed up again for a while.

I don't know why they disappear after a while or where they come from in the first place, but they don't seem to cause any long-term issues.

Maybe the biofilm that builds up on all surfaces over time is unfavorable for them, and that's why new tanks work better. Or maybe something eats them or filters out their eggs/spores, like sponges that first need to establish themselves in the sump or plumbing before they become effective.

Fascinating creatures, as long as they don't cause trouble, I kind of like them