Please help identify this creature in my tank

[TTUHoopsFans]

I have seen a few of these in my tank, and have no idea what they are. I caught one the other day after removing water and cleaning the substrate with a vacuum. I know there have to be several of them. At first I thought it was a shrimp or baby crayfish, but I don't think it is. It swims very quick and zig-zag like. It's very tiny, this is a zoomed in picture.

I first noticed these when removing 5 marimo moss balls from my tank to soak in a clean container of cold water while cleaning out my tank. When I went to reshape the moss balls and put them back in my tank, I saw 2-3 of these things swimming around in the container. I thought maybe it was baby crayfish because we used to have a crayfish, but it died about a month ago.

Hopefully we can identify what it is, and if we can, does it present a problem for my tank?

 

[charliebankston]

I think it's a daphnia. Fish will eat them.

 

[TTUHoopsFans]

I think it's a daphnia. Fish will eat them.

Thanks for replying. I just googled daphnia and watched a video of them swimming, and it doesn't quite look like that:

 

[charliebankston]

Oh OK, and it's not a squirrel, so let me think...

 

[charliebankston]

Could be copephods or amphipods. I'm not sure if either of those live in freshwater or not. What is your tank stocked with?

 

[dartzy2]

How about a scud?

 

[charliebankston]

How about a scud?

That's prob it

 

[TTUHoopsFans]

How about a scud?

Yes, I just googled a scud and it does look like that! I wonder how I got them, I guess plants or moss balls from the aquarium store?

It looks like them from this video, for sure, even the way they swim.

Thank you!

https://youtu.be/F0sKU9x1SV8

 

[charliebankston]

Fish will eat them, and they love to eat decaying matter and even algae. They mostly come in on plants, but can come from other used sources too