Far from an expert but I think you’re right about planaria is always mentioned having diamond shaped heads. And a quick google does look like it could be some kind of leech. Or some kind of flatworm maybe.
Where did these come from and how are you going to get rid of them? I have some plants and snails I want to treat with some kind of dewormer (without killing the snails) before moving them to my other tanks and kind of getting information overload. And it’s got some kind of white hair algae in it.
Aqua-66 
Looks like it might be a planaria.
They’ll eat all your shrimp. There are a few treatments to get rid of them.
A leech I believe.
Far from an expert but I think you’re right about planaria is always mentioned having diamond shaped heads. And a quick google does look like it could be some kind of leech. Or some kind of flatworm maybe.
Where did these come from and how are you going to get rid of them? I have some plants and snails I want to treat with some kind of dewormer (without killing the snails) before moving them to my other tanks and kind of getting information overload. And it’s got some kind of white hair algae in it.