Jellyfish...? (it swims)

[JasonVH]

Just found this thing.. swims like a jellyfish except "constantly busy fast". What is it? If it's a pest, how is it dealt with? Not putting this one back in tank, a little worried 'if you see one, there's more hidden'.


Refrigerated it to get still shots:

 

[vetteguy53081]

Just found this thing.. swims like a jellyfish except "constantly busy fast". What is it? If it's a pest, how is it dealt with? Not putting this one back in tank, a little worried 'if you see one, there's more hidden'.


Refrigerated it to get still shots:

Upside down jelly which are showing up as hitchhikers and are not long lived

 

[JasonVH]

Upside down jelly which are showing up as hitchhikers and are not long lived

Thanks and sure hope so, was worried about it being a free swimming phase of hyroids or something. It was discovered in the HOB filter, under the basket packed with polyfil. Aren't those things photosynthetic?

How do most of them hitchike? Haven't gotten new fish or corals for several months. I did get a new batch of live phyto and copepods last week. Is it possible for them to sneak through filtered sea water? The LFS gets their saltwater via the ocean out by Catalina Island, iirc.

 

[vetteguy53081]

Thanks and sure hope so, was worried about it being a free swimming phase of hyroids or something. It was discovered in the HOB filter, under the basket packed with polyfil. Aren't those things photosynthetic?

How do most of them hitchike? Haven't gotten new fish or corals for several months. I did get a new batch of live phyto and copepods last week. Is it possible for them to sneak through filtered sea water? The LFS gets their saltwater via the ocean out by Catalina Island, iirc.

May have come in with pods. Generally its in the water with new fish, coral or LFS purchase

 

[JasonVH]

May have come in with pods. Generally its in the water with new fish, coral or LFS purchase

Thank you! Found a video of captive bred jellies.. showed one that looked very much like it. Before the arms grow.

 

[EeyoreIsMySpiritAnimal]

That is likely the Medusa (free swimming) stage of a hydroid. If so, nothing to worry about as these hydroids (Medusa and polyp stages) usually only appear in new tanks and are quickly outcompeted for food.

Pretty cool to watch though!