Mysterious worms infestation

[Bray25]

Hi I have an infestation of worms in my tanks which I can see squirming all over the tank walls, if anyone knows what they are and if they are harmful to the fish that would be good to know and also if anyone knows any methods to get rid of them? I've cleaned and re set up those tanks numerous times and they always seem to reappear, I've added some photos I also have snails in the tank if that makes any difference

 

[Colin_T]

Are they in the water?

They look like detritus worms that normally live in the substrate. however, if you use chemicals/ medications, or the tank water quality deteriorates, or the substrate gets dirty, the worms come out of the substrate and try to find a new place to live. They can't get out of the tank and end up swimming around the water or crawling up the glass.

The easiest way to deal with them is by doing a 75% water change and gravel cleaning the substrate every day for a week.
Make sure any new water is free of chlorine/ chloramine before it's added to the tank.

 

[Salty&Onion]

Are they in the water?

They look like detritus worms that normally live in the substrate. however, if you use chemicals/ medications, or the tank water quality deteriorates, or the substrate gets dirty, the worms come out of the substrate and try to find a new place to live. They can't get out of the tank and end up swimming around the water or crawling up the glass.

The easiest way to deal with them is by doing a 75% water change and gravel cleaning the substrate every day for a week.
Make sure any new water is free of chlorine/ chloramine before it's added to the tank.

Yes and if they are big enough I would remove some of them with tweezers.