Grass Shrimp Breeding Success

[DaJMasta]

Some may have seen the result of this at our last meeting (they were swimming around in a small tank with some frags cut from the main reef), but in the last month I've managed to get what I think are called grass shrimp (clear saltwater shrimp sold as feeders) to spawn in my tank, and I've raised 20-30 of them to settled juveniles.  I actually raised the first two 'accidentally' in a container that was floated in the tank with its parents and got a little natural water exchange with it on almost solely artemia nauplii, then I collected a much larger batch of larvae and raised them up in a bucket like my other attempts and had nearly all that were caught, settle.  I also caught them in the display portion of the tank, where their parents were living in the sump, so they seem to be quite durable as larvae and are likely some of the easier shrimp to get to settle.

 

I don't have a comprehensive breakdown of the timeline they settle in or my exact methods - I wasn't expecting success and had two runs overlapping, so I just wasn't recording details as I normally would - but I did get some video as larvae and some video as settled juveniles, which I've put together here:

 

 

For the basics, this is a rundown:

Grass shrimp - mostly clear, develops darker patterns (and maybe cloudiness) in a few days in response to the environment, a little smaller than a peppermint shrimp when fully grown, fairly outgoing and inquisitive, happy to live in groups and get along with each other

 

Larvae are strong swimmers and are phototactic, so they can be caught pretty easily with a source of light and dark surroundings.  Larvae don't seem to need any flow (light turnover to keep parameters consistent is still advisable), can eat decent sized foods (artemia nauplii from day one), and aren't particularly disoriented by multiple light sources.  They can be fed several times a day with prey organisms and you will see modest feeding amounts disappear within 12 hours.  I also fed mixed copepods, it was not the majority of things available and I can't say for sure if it was important for their development.  They don't seem to have much trouble living with adult copepods, and don't need immaculate water quality.

 

Settled juveniles still swim some, but larvae swim always tail first and juveniles do walk/run and swim head first as a normal shrimp.  You probably want to keep them away from predators, stinging corals, and powerheads while they're young, but I've had a couple from an early batch roam in my tank and they've lived alongside their parents (3-4x the length) and even have gone through the powerhead again to make it back to the display.  Adults and juveniles are basically detritivores, but seem to like meaty frozen food over pellets.  Full sized foods (like bloodworms) may be more difficult for the small shrimps to eat, though they'll take whatever they can get into.

 

With the sump on the opposite photoperiod from the display, I don't know exactly how frequently they spawn, but I hope to get at least a few more batches to raise up.

[gastone]

I’ve always been fascinated by reproduction in our closed systems.  Very nice!
 

[DaJMasta]

A little update with a useful tidbit: I've observed some of these little guys carrying eggs already, so apparently around 2 months from settling as juveniles, they can start producing their own offspring.  Quick turnaround!