Help identifying tiny worms

[JessTheMess92]

So the TLDR: I need help identifying these tiny worms. 

I have a 125 gallon I planted it and set it up 5 weeks ago. I've been cycling it before I put shrimp or fish in it. There are bladder snails that hitchhiked on the plants though. About a week ago I noticed these tiny little worms on the glass. They only seem to hang out on the glass. They are maybe .2 or .3mm long. I thought they were planaria and used panacur c to kill them but they didn't die and I looked up how big planaria are and they are supposed to be like .1 to .3 inches so yeah basically I'm just curious what these guys are and if they would be dangerous to fish  shrimp  snails, or anything else i might put in the tank. Thanks :)

[gcalberto]

Honestly those look like garden variety worms that make up what we call infusoria or aufwuchs. Really small fish and fry eat them, but other than that they are completely harmless 

[ange]

They look like rhabdocoela in the photo that you posted. They're not harmful but also aren't nice to look at. If they have a more arrow shaped head region, they're likely planaria. Planaria can be harmful to some invertebrates however there are several solutions such as traps/water additives for eliminating infestations.

[Mmiller2001]

Good article just because.

https://fishlab.com/planaria/

They don't look like Planaria, but you can see what the harmless flatworms look like.