What are those mini shrimps in my reef?

[schafon]

Hi everyone.
I've noticed for serval days now that I have mini shrimps swimming at the same spot.
I have 3 cleaner shrimps, and 3-4 sexy shrimps.
I know for sure that the cleaners are spawning regularly, but from what I've read online the babies were supposed to be dead by now by filtration / other tank mates.
When I look at this small hole I can see many shrimps in different sizes, the biggest ones are the same size as adult brine shrimp!
Is there a chance that they will survive in the tank at this point?
Adding video for identification:

Mini shrimp in reef tank

youtube.com

Thanks!

 

[Tamberav]

Might be live mysid shrimp.

 

[saltyhog]

Mysid shrimp. Not related in any way to your other shrimp. Great hitch hikers but usually get eaten before too long.