What are these shrimp like creatures?

[poconojoe]

They are clear and tiny, maybe a 1/4" long, and look kind of like shrimp. They seem to want to ball up when disturbed. I've seen them on my submerged pump in the past. Just today I repotted a plant and a few were on the soil as I pulled the small pot out of the pond.
I'll post a couple of pictures, but I don't know how clear they will be...

 

[JamieB]

I’ve no clue, but I get them too. My fish eat them. So perhaps they are a large daphnia or nymph form of some bug.

 

[poconojoe]

JamieB...
I hope they're not harmful.
If your fish are eating them, I guess they're OK. Hopefully they are a sign of a good ecosystem. Some kind of freshwater shrimp?

 

[doobry]

water fleas maybe

 

[Jhn]

Those are gammarus shrimp, freshwater scuds. Yes, they are a sign of a healthy diverse ecosystem and a natural food source for fish as they reproduce readily. I have purposely introduced them to my ponds in the past.

They are found in fresh, brackish and salt water, in reef tank systems they are cultivated in refugiums as a supplementary food source for hard to feed fish.

 

[poconojoe]

Those are gammarus shrimp, freshwater scuds. Yes, they are a sign of a healthy diverse ecosystem and a natural food source for fish as they reproduce readily. I have purposely introduced them to my ponds in the past.

They are found in fresh, brackish and salt water, in reef tank systems they are cultivated in refugiums as a supplementary food source for hard to feed fish.

Thank you! I was hoping they were something good.
I wonder how they got in there? Maybe hitchhiked on a plant? Or do they somehow evolve naturally?

 

[Oaklandopen]

That actually looks like what I spotted yesterday I'm the roots of my hyacinth. Freaked me out for a second because it reminded me of the aphids from the movie a scanner darkly