[SallyLoudmouth]

Bought this from a LFS and they had no clue what it was. I saw it in with the shrimp and bought it.

 

[payluder]

Pelia moss it looks like it

 

[PMoore]

+1... It's Pellia Moss

 

[WaterLife]

I think it's Subwassertang/Susswassertang. (Lomariopsis sp)
Called "round pellia", but is not actually pellia/liverwort (Monosolenium tenerum).
Both look very similar, though some slight different characteristics.

Would be easier to tell if some single strands were pictured, not in a clumped mass.

 

[Nordic]

As far as I know it is a fern... Freshwater seaweed is another common name for it.

 

[SallyLoudmouth]

Thanks!

 

[JJ09]

It looks like subwassertang to me, too. But I've never had pellia so don't know the differences up close.

 

[AquaAurora]

+1 looks like subwassertang

 

[Mikeygmzmg]

Yep subwassertang for sure.

 

[RWaters]

Another vote for subwassertang.