Tiny reddish shrimp found in the back chamber

[DaJMasta]

Found these little guys in the back chamber running around on a piece of the skimmer.  I've got a bunch of shrimp in the tank - skunk cleaners, a single peppermint, a couple kinds of pistol shrimp - but these don't look like juveniles of any of them, really (maybe peppermint?), and they act and move like adults, so they're not larvae.  The biggest I've seen is about 5mm, but the size range is like 3-5mm, so they could be from a spawn and still growing.

 

 

[empresto]

That's really cool! Curious to hear what others have to say.

[Justind823]

Looks like some sort of Mysis to me!

[johnmaloney]

Still growing I bet, cool find!

[debbeach13]

That’s awesome 

[michael_cb_125]

They are mysid shrimp. A good sign to have breeding in your system.

They will reproduce in waves. You will have a large population which will rapidly decrease, only to repopulate again. For such a small animal they need a lot of space and are highly cannibalistic.

 

[DaJMasta]

I think that's the best guess so far, at the very least, but they look more like images of marine mysids by eye rather than under the microscope.  I've got a couple of small fry tanks that I dumped some into to try and spread out the colony - if they can take hold I may even try to culture them, though I know that's no easy task in small systems.

 

 

[michael_cb_125]

Also remember that there are many species of mysid in bothe fresh and saltwater

[mcarroll]

Is the coloration a coincidence of the photograph?  Everything in frame looks peppermint color.

[DaJMasta]

That is actual coloration under the microscope, but it's faint enough that it's hard to discern by eye.  I do have a peppermint shrimp, though only one, so there is some possibility it was carrying eggs when it came in months ago.

 

That said, the images I could find of newly settled peppermint shrimp online seemed to be more... leggy.  Spindly legs, antennae and maybe paddle appendages which seem much smaller/more normally proportioned on these guys.