What These Shells?

[N1z]

I found these in my old tank wot u think they are?

I also found a smal tube worm on one of the broken ones if that helps.

 

[demonmagus]

They look kinda like mussels, but they probably aren't...

 

[scott67892002]

yep fresh water muscles!

 

[N1z]

lol how the hell into my salt water haha ok cheers