Clear see through sack with white inside that looks like worm?

[PaddSter]

Hi all,

another critter/pest ID post.
Just noticed it today while hawing a long look on my reef tank.

Not sure what they are. Haven't seen them before and I usually do have 40-45 min sit down and watch carefully everything every week.

They are like see-through little "baby clam-shaped" sacks with something white inside. It appears like head of white flat worm but may be as well something completely different.

Total size about 2-5mm

I have about 5 of them spread not far from each other. On 2 rocks that are close by each other.

Any ideas?

 

[Ron Reefman]

No idea at all. A better photo might help. Any chance one could get pulled out of the tank for a photo?

So lets get a bit more help here. Hey #reefsquad !!

 

[Retro Reefer]

Agree on better picture. Can you turn the blues off for a pic?

 

[KJ]

Whelk eggs?

 

[PaddSter]

Not sure if that will be any better.
It's very small.

I doubt it's whelk eggs as I don't have any.. I guess.. I do have 3 sand sifting conch and they didn't attack anything ever.

Plus these little things are separate. Each one of them in different place.

Let's try to take one of them out..

 

[KJ]

Tunicate.

 

[PaddSter]

Thank you for all the ideas and advices