Any idea...

[mamedina]

...what these are? They’re about the size of a sesame seed and don’t move. I was thinking snail eggs?

 

[cloak]

Spirorbid worms most likely.

 

[jda]

Do you have nerite snails?

 

[Crabs McJones]

Nerite snail eggs most likely

 

[mamedina]

Yup leaning to the eggs....will they actually successfully reproduce

 

[PhreeByrd]

They are not eggs. Snail eggs and most all other eggs are laid in clusters. I agree that they are most likely spirorbids. Harmless filter feeders, and very common. Take a look with a good magnifying glass. Spirorbids have coiled shells and generally very small feathery feeding tentacles.

 

[Rybren]

I have some that are similar looking. When viewed with a jeweler's loupe, I can see tiny yellow eggs inside the sac. I'm thinking nerite eggs.