Fish ID? Is it a fish?

[The Masked Shadow]

I saw these weird leech-looking things. They were in the Otay River (downstream of the reservoir, the river is barely a river, more like a large stream), Southern California. They were in a stream, moving, not fast, but in the fastest area of the river. They were in what seemed to be an organized pattern. My question is is this a fish? Is it a worm? Is it some kind of insect eggs or larvae?

 

[The Masked Shadow]

Apparently the picture didn’t add onto original post - here it is

 

[duanes]

Look like some kind of insect larvae, aquatic stage, maybe black fly, but that's a wild guess, need a more focused close up.
I tried to zoom in, but that blurred them out too much..

 

[fishguy1978]

Did they go or did they stay if you put your hand in the water?

 

[Midwater]

Did they go or did they stay if you put your hand in the water?

Did they attach themselves to your hand and suck the blood out of it?

 

[The Masked Shadow]

View attachment 1517917
Look like some kind of insect larvae, aquatic stage, maybe black fly, but that's a wild guess, need a more focused close up.
I tried to zoom in, but that blurred them out too much..

I’ll try to get a better picture, but that looks like a rough ID of what they are.

Did they go or did they stay if you put your hand in the water?

I didn’t, but I guess I’ll try.

 

[phreeflow]

That’s disgusting