Bugs/worms in tank? help please

Hi everyone,
I’ve been having a pretty bad brown algae spike in my 20-gallon for the past few weeks. I’ve been doing water changes and trying to keep it under control. I did about a 60% WC yesterday and the tank was looking good. It still looks great this morning- the water isn’t yellow and I don’t see any new spots of algae. However, when I was feeding them, I noticed several little inch worm looking bugs on the top of my tank. Of course I freaked out and called for my dad to see what they were. I tried to take a picture but they were too small to show up on camera. Tiny little light brown worm things. At first I thought they were just some dried blood worms I dropped, but then I almost passed out when I saw them moving. I lifted up the lid of the tank and there was a considerable amount of them under. My dad was able to get them all off and there was only one in the water he scooped out. Is this just a freak worm infestation incident, or should I be worried that they came from / are being drawn to the tank???? Parasite maybe? I haven’t had much luck with my tank so I want to make sure this isn’t something about the water or fish.

 

Maybe detritus worms? It would make sense if you did a large WC that they would come out

 

Maybe detritus worms? It would make sense if you did a large WC that they would come out

I’ve never heard of those. Are they harmful to the tank?

 

I’ve never heard of those. Are they harmful to the tank?

No, they’re a sign the tank is established, though if you see them you might consider vacuuming your gravel more. You can compare the worms you have to pictures of detritus worms online. Detritus worms usually hang out in the substrate and eat detritus and other organic matter. It’s not unusual to see one freely swimming or to have them come out during a water change. If you vacuumed gravel they may have been stirred

 

No, they’re a sign the tank is healthy. You can compare the worms you have to pictures of detritus worms online. Detritus worms usually hang out in the substrate and eat detritus and other organic matter. It’s not unusual to see one freely swimming or to have them come out during a water change. If you vacuumed gravel they may have been stirred

Thank you so much. That’s a relief. I did a big water change yesterday. I was just so surprised because they were mostly hanging out on the lid and outside of the tank.. I don’t see any in the gravel now so they probably all just got kicked to the top after the WC.

 

This is the best I could do for a picture sorry it’s blurry...