Mystery jellyfish?

[Spaceshrimp]

So I was just looking into my tank after the lights have been off for a bit and i saw what looks to be a tiny jelly fish swimming around its to small to take a picture of but its clear and i can actually see its body opening and closing to move and i was wondering if anyone has seen this in theyre tank before

 

[Old Fritz]

Probably a hydroid. They don't really do anything and inverts like peppermint shrimp and like to eat them I believe correct me if I'm wrong

 

[Spaceshrimp]

Probably a hydroid. They don't really do anything and inverts like peppermint shrimp and like to eat them I believe correct me if I'm wrong

What shape are the hydroxide

 

[Retro Reefer]

Probably a Hydriod in its medusoid stage. They look like tiny jelly fish during this free swimming stage

 

[Spaceshrimp]

This is the closest picture ive found to what i see in the tank