Can anyone identify what type of worm this is?

[Suku]

All I have is this video. It's moving downward on my glass. I also saw a baby moving on the driftwood I have. So far I've only had two sightings.

I think we can rule out planaria because it doesn't have the triangular head? I hope it's not something harmful to my tank.

My tank parameters are normal. It's a 40 gallon community tank with guppies, neocaridina shrimps, corydoras, and ramshorn snails. I feed every other day and the food is never left over.

[Colu]

It could a planaria worm

[patricia]

planaria

[shkote]

Looks like a rhabdocoela worm, totally harmless. 

[Lizzie Block]

Lynze has it. Gotta be something other than planaria, the head isn't triangle shaped in the slightest. Not harmful 👍

[Suku]

I'm just curious @patricia and @Colu What makes you think it's planaria? I had ruled it out because it doesn't have a triangular head.

 

@Lizzie Block @Lynze Do you know how rhabdocoela usually get into the aquarium? Am I overfeeding?

 

Thank you all for the input!

[Daniel]

Invertebrates that fill niches in your aquatic ecosystem are rarely something your fishkeeping habits caused.

Yes, a hydra population explosion does have something to do with all that bbs you are feeding, but not that first hydra.

Aquatic ecosystems usually have a diverse array of invertebrate species that help shift energy up and down the food chain. Anytime you introduce fish, plants, driftwood, etc. from an environment outside of your own, you will inevitably bring part of the invertebrate diversity from the other ecosystem.

More harm is likely to come to your aquarium and its fish with an attempt to control this bit of ecosystem diversity than doing nothing.

[shkote]

Seeing a few every now and then is normal and as @Daniel mentioned, part of a working ecosystem. It's a good sign that your tank is healthy. If you start seeing hundreds or thousands of them, then maybe it's a overfeeding issue.

I've started up bare bottom empty fry tanks with no plants and had them show up, like magic. They reproduced quite a bit from heavy fry feeding. It worked out though because their numbers multiplied while the fry was small and the second they were big enough to munch on worms, they had a whole buffet of crawlers to stuff themselves on. Now I rarely see them in those tanks, so they must be tasty little critters. 

They're pretty common in my shrimp tanks where there are no fish to take them out. I like to think of them as roommates. I've seen people advise to tear down entire tanks and restart from just a handful of worms and as @Daniel said, it is far more harmful to your other inhabitants trying to control nature.