Tiny Worm Problems..

[H]-[H]

I noticed some worm like creature wriggling around the water in my tank.. They are really really tiny & I have to look really closeup to notice them.. My question is are they harmful to fish? I don't know where they come from..
It's just been a week since I did wc..

 

[Lupin]

Could be planaria or detritus worms. It means you're either lagging on tank maintenance or overfeeding. Correct both. No, they're not harmful to fish. Most fish will in fact eat them.