What is this?

[RyleeA33]

I’m having trouble figuring out what this thing is, a couple of them came on a clump of spaghetti algae I had purchased. I will post some pictures down below. Sometimes I will notice them swimming through the water column like a jelly fish when I shut off the pumps for couple minutes to feed my seahorses. These organisms are so tiny, when I was feeding live baby brine shrimp in the tank once, I noticed one these organisms touch a bbs and it paralyzed or killed it. From a side profile of the organism, they look like tiny clear octopi.

 

[flsalty]

Hydroids in the Medusa stage.

 

[jeffchapok]

Agreed. They'll go away soon on their own.

 

[RyleeA33]

Thankyou! So glad to know what they are now!