Can anyone ID these worms?

[Paulm7373]

Friend of mine had noticed these white worms around 10mm long appearing on the glass of her tank after completing a water change. Livestock in the tank are peppermint bristlenose plecos and ghost shrimp. Does anyone know what type of worms these are and how these have appeared?

 

[Caliban07]

The one on the left is planaria the other is another type of flatworm often deemed harmless whereas planaria can be an issue for shrimp keepers I believe.