Are they little like fleas?
Or wiggly or flat and like a worm? Planaria check that. Some swim all around and when they are bigger, they have a arrow pointed shape head flat worn. I can not really see what it is from the pictures.
New to FW fish? First tank in a long time or EVER??? Need some info on keeping fish?
Start here - Aquarium Advice Article
FW Favorites right now Clown Loaches, any shrimp - SW Vase Red Mangroves