Aquariums: What are these worms in my aquarium and are they bad?

These look like planaria to me. Yes they are typically considered bad. They will eat your inverts.

Planaria have like a triangle 🔺️ for a head. They bad. These don’t have triangle for head and so, are not planaria. But, your certainly over feeding a tad, so cut back a bit. And 5 days of food followed by a fast will keep the fish healthy.

Im having the same issue, tons of these little guys in my floating plants.

There are commercial treatments for planaria you can use, but your water will foul due to the massive die-off so be prepared to make water changes.

You can manage the population but they are nearly impossible to completely remove unless you take out all the live stock and basically nuke the tank. You would need to get new plants, too.

This does not look like planaria to me. This looks like detritus worms – perfectly harmless and good little buddies for your ecosystem.