What is this?

[Pimp My Fish]

So I bought a clown goby yesterday and it was a bit expensive, so the lfs store owner offered me something else included for that price. Since I don't have adequate coral lighting yet, he gave told me he would give me something that is guranteed to grow without light and gave me this purple thing. According to him, it was some sort of sponge that needs no special care, but I have no idea what to do with it. Can someone ID it?

PS: I didn't expose it to air when acclimating.

 

[Sniperhank]

It might be a sponge. If the tank hasn't been set up for very long it might struggle to get the nutrients it needs from the water column. Many sponges are quire hard to keep.

 

[Pimp My Fish]

Thanks for the input! My tank is established and is going for 2 years now, but it's only 10 gallons so it might not be able to support it.

 

[Sniperhank]

Maybe not. Sure is pretty though. One of the lessons I learned on early in my fish keeping is that anything that needed extra feeding from liquid foods of phyto or whatever are simply too much hassle unless you have a huge water column or amazing filtration to remove it from the water column shortly after. I've read about those that would pull NPS coral out of the tank to feed in a separate container...but that would be a deadly idea for a sponge. Too much chance at air getting in there.