Need help identifying potential pest

[Alral1988]

Hey guys, I've recently started my very first planted tank. So far I'm having a blast with it as well as my shrimp. I do have a snail out real beginning which isn't great but I can keep it in check.

My question is about this tiny guy below. It almost looks like a snail or something, but relative to its size, it moves way too fast. If anybody knows what this is and could tell me about it I would appreciate it. Thanks

 

[xwesx1978]

do they have diamond shaped heads or tentacle heads ? its either planaria or hydra

 

[Alral1988]

I can't tell they are tiny. It looks more like antennae if anything. Considering this is the first I've dealt with them can you give me any info? All I have in the tank currently are RCS, plants, and some pesky snails. Will this be harmful to the tank or any inhabitants? Where did it come from? Any help is appreciated

 

[xwesx1978]

planaria

Hydra


hydra is the one you dont want they can sting and kill your shrimp

 

[xwesx1978]

im thinking its planaria because you said they were fast , read this

Planaria In Fish Tank | The Planted Aquarium Blog