What is this worm??

[yassy]

Yesterday for the first time, I saw this work. It looks like earthworm but wonder what it is..

 

It was in shrimp only tank and funny thing is, that tank has many shrimp and I barely see dead shrimp and it is the tank that is doing pretty well.So, I do not think this thing would not be munching on shrimp I think.

 

Anyone has any idea as to what it is?

 

I removed it after pic and keeping eye closed on the more worms but I did not find any today.

[Luxa]

Looks to me like a garden-variety aquatic earthworm. Certainly not predatory.

[yassy]

thank you.

 

[Biotope Biologist]

Fascinating! That honestly looks like a freshwater polychaete! 

 

I've never seen a freshwater one and indeed they are mostly marine but I honestly think those are tiny chaeta along each body segment. Look at the irridescence on it, beautiful! I have something of an obsession with these worms. Although some are predators, I believe most freshwater variety are detritovores eating leftover food and plant waste.