What kind of Jelly?

My buddy got a Jelly Fish for his tank today - apparently, it's mainly photosynthetic but nobody knows what species it is. Any ideas? It rests upside down on the bottom with its tentacles up, then swims around, then rests again. Almost looks like sand on it, but, it's not.

 

Well, it looks like an upside down jellyfish to me.

upside down jellyfish - Google Image Search

 

+1, upside down jelly fish.
Best of luck!

 

Thanks, appreciate it! Any suggestions or anyone have experience with one of these? It's a FOWLR. (Actually, this is the only invert aside from snails / one coral banded shrimp).

 

I know vivid aquariums used to sell it and they had a video on it...very cool. Check out that site and see if they have any info

 

Ive gone through 2 actually.... if you have the appropriate lighting it will noticably grow, or shrink if not well lit. the only thing that keeps me from trying it again is, for one, they arent strong swimmers and always end up stuck to the filter intake (ussually tears em up pretty bad, its depressing) , for two, lunch time for anenomes...

 

It is a Cassiopeia Andromeda sp. a.k.a Upside jellyfish.
They swim right side up but often are found upside down to be able to ensure that their zooxanthellae receive the light they need. Really, the only jelly for a basic aquarium, plus fairly hardy!

 

I had one in my 12G with 65W of CF and it wasn't enough lighting for it, when the 24W that the JBJ comes with wasn't good enough. I had to give it back to my LFS so it wouldn't die. Just to give you an idea of lighting needs. I'm sure if I had the MH or T5 on it, it would have been fine. It was neat the first week, but was pretty boring after that. It was more trouble keeping it from getting stuck in the overflow filter than what it was worth. It was beat up pretty bad from the JBJ filter, but is still alive and doing good in my LFS DT.

 

the last one i had was 2in across when i bought it and eventually got about 4 in across and as the life of the CF's wasted away he was about as large as a quater before he was pronounced MIA

 

Thanks for all the responses, guys I appreciate it - it's an interesting critter to watch scoot around the tank, hopefully it does well.