Egg of?

[Kobooi]

While leveling the sand in one corner of the tank (too much sand had collected there over the last month) I found a couple of these, burried vertically in the sand.
I think they're eggs of something? They're filled with water, and what looks like a tiny embryo when you look through them against bright light.

 

[Chrisv.]

Looks a bit like a zoa that's lost its head. Do you have zoas?

 

[ISpeakForTheSeas]

Personally, I'd be inclined to think it's some kind of tunicate, or possibly some kind of worm (though tunicate would be my first guess), but I don't know for sure.

 

[Kobooi]

I do have zoa's, though none missing. I would believe they would shrivel up and disappear.
Wouldn't a tunicate "deflate" out of the water?

 

[ISpeakForTheSeas]

I do have zoa's, though none missing. I would believe they would shrivel up and disappear.
Wouldn't a tunicate "deflate" out of the water?

I’m not sure honestly- I think most would, but with a sand dwelling one, I don’t know. Again, if not a tunicate, my next guess would be a worm (or worm-like species we’d call a worm) of some kind. Either way, I feel fairly confident in saying that I don’t think it’s an egg. I’d guess the embryo you’re seeing is probably the creature’s heart.