What Was Up With My Shrimp?

[PrairieSunflower]

I have 4 amano shrimp in with my fish and snails.  Normally, they just crawl around munching on stuff.  Well, last night around 10pm they were absolutely bouncing off everything even the fish and swimming in every direction at every level of my tank!  There was nothing that I test for that was off at all, I checked the temperature and it was stable as usual, they were feed early in the morning and nothing contaminated the tank at any point.  I have never ever seen them do that before.
 
I was convinced I'd wake up this morning and they'd all be dead... but no... back to normal like nothing happened.  I did my weekly water change this morning.

 

[ech0o]

Breeding behavior, the males will swarm when the female is in heat.

Expect a berried female soon!

 

[PrairieSunflower]

Ooooooooooooo!  I should look up breeding them... I just remember reading that the babies need brackish water.  I wonder if I could set up a little tank for that.  Probably too difficult!

 

[Baccus]

It could have been males looking for ready to breed females, but that shouldn't also send the fish into a mad panic.
 
I am wondering was there a sudden change in the weather? A new low or high moving into your region? Fish and shrimp are very attuned to barometric pressure, just as they are well aware of any seismic shifts in the earths crust.

 

[PrairieSunflower]

No, the fish were fine and normal... other than getting freaked out from time to time if a shrimp jumped on them.
 
The weather has been quite mild with no big changes.

 

[ech0o]

Yea i am betting on breeding behavior.  They generally only do it when they sense a female ready to breed, which is why I believe one of your shrimp may be female.