ID Needed - Is this a jellyfish ephyra?

I found a number of these cup-shaped creatures that look a LOT like Jellyfish ephyra or medusae in a kreisel tank I was using for seahorse fry. There are no seahorses in there currently, but a very large population of various copepods, mostly Tisbe. They are between 500 and 100 microns across, and have long, thin sweeper tentacles not clearly visible in the picture. To the eye, they have a very red/orange color. They are radially symmetrical, and are octagonal (have 8 main tentacles). Here is a picture:

 



 

Anybody know what these are?

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Could be Hydroid Medusa.

OK, I've got some Pancure.  That should take care of them!

I see stuff like this now and again in my larviculture...it's always hydroids.

Looks like. They are awfully cool to watch under the 'scope though.

--Andy, the bucket man.
"Not to know the mandolin is to argue oneself unknown...." --Clara Lanza, 1886

Put it in a pico tank on your desk! (: I used to keep them like that, it was fun. Later got some that looked the same but were actually the smallest stage of a rather good size brown atlantic anemone, which is much more fun to keep.
Kate