Pulsating pink jelly-like creature

[onlyreefers]

I have some sort of new creature on my glass. It is small, circular and pink. It constantly pulsates, in a contracting, circular motion. Glanced over the hitchikers guide and did not see anything similar.

 

[onlyreefers]

Different picture…

 

[EeyoreIsMySpiritAnimal]

Medusa form of a hydroid, probably. How old is your tank?

 

[onlyreefers]

Medusa form of a hydroid, probably. How old is your tank?

This setup is 6 weeks old.

 

[EeyoreIsMySpiritAnimal]

This setup is 6 weeks old.

These are very common in new tanks and will go away on their own soon

 

[onlyreefers]

These are very common in new tanks and will go away on their own soon

Thanks! Just never seen or heard of anything like it

 

[EeyoreIsMySpiritAnimal]

Thanks! Just never seen or heard of anything like it

You're going to find all kinds of cool stuff

 

[onlyreefers]

This thing has grown, it’s awesome, but still can’t identify, just pulses 24/7. Hard to get a good pic.

 

[onlyreefers]

 

[Alexraptor]

I'ts really hard to tell from those pictures, but is it laying loose on the sand, pulsing with frilly bits/tentacles pointed towards the sky?

Because I almost think it looks like an upside down jellyfish, Cassiopeia sp.

 

[onlyreefers]

I'ts really hard to tell from those pictures, but is it laying loose on the sand, pulsing with frilly bits/tentacles pointed towards the sky?

Because I almost think it looks like an upside down jellyfish, Cassiopeia sp.

I don’t know about how loose. Thought about poking near it to see if it moved. Started on the glass and has been resting in the sand since. It’s typically stationary. I never spot it moving.

I did take a google search of the upside down jellyfish, and it looks like that’s exactly what it is!! Thanks!

Do they sting corals, people, fish? Seeing that they are typically sand resters on the search.

 

[Alexraptor]

I don’t know about how loose. Thought about poking near it to see if it moved. Started on the glass and has been resting in the sand since. It’s typically stationary. I never spot it moving.

I did take a google search of the upside down jellyfish, and it looks like that’s exactly what it is!! Thanks!

Do they sting corals, people, fish? Seeing that they are typically sand resters on the search.

Then congratulations are in order, one of the more unusual hitchhikers!

To answer your question, they are known to have a mild sting, strong enough to produce an itchy rash on human skin. But it's purely defensive, they don't have long trailing sweepers like more predatory jellyfish do. Instead they feed like photosynthetic corals, and spend most of their time on the bottom, soaking up the light for their zooxanthallae.

Personally i'd risk keeping it, as it's one of very few jellies that can actually be kept in a normal tank.