OK, I did a little digging and here is what I found...
The grass, glass, or ghost shrimp, whichever you prefer to call them are in the Genus Palaemonetes. There are several species native to North America. All reach a maximum size of about 1.5" with females being larger than males.
P. Pugio- Daggerblade Grass Shrimp
P. Valgaris- Marsh Grass Shrimp
P. intermedius- Brackish Grass Shrimp
P. paludosus- Eastern Grass Shrimp
P. kadiakensis- Mississippi Grass Shrimp
P. texanus- Texas Grass Shrimp
There are also a few cave dwelling species of very limited range.
The ones I have personal experience with are mostly P. pugio and P. vulgaris. They are both found in brackish waters along the east coast. P. pugio can survive in low salinity levels but cannot reproduce in them. P. valgaris can only survive in salinities as low as 5 ppt. P. intermedius is also found along the east coast in brackish waters. It is also only capable of reproducing in brackish waters. This makes these 3 species unsuited for a pond.
So, that leaves P. kadiakensis which is already mentioned above with the fine photograph by bobad. The other species of value to pond owners would be P. paludosus and P. texanus.
P. texanus has a very limited range and is very uncommon. P. paludosus is very cold water sensitive not being able to survive in water temperatures under 50 degrees. It is the species that is found throughout Florida and if you have ever seined in any lake in Florida or fished with grass shrimp for RES in Florida, you’ve definitely come across them. So unless you live in the far south, that only leaves P. kadiakensis as an option.
P. kadiakensis is native to the Mississippi River drainages. They live about 1 year and usually only have 1 brood per year, but apparently some populations may have 2 broods. The length of the breeding season is dependent on latitude and is longer in southern populations. In Illinois and Michigan ovigerous females are present April-August. In Louisiana they are present February-October. The number of eggs produced ranges between 8 and 160. The fecundity is a function of length of the female incubation period (temperature dependent) and varies from 2 to 3 weeks. They have six stages of free living larvae that usually mature when they reach a length of 20 mm. Adults usually die after reproducing, but females in some populations may produce a second brood. The adults usually disappear in populations in late summer or early fall after death.
P. kadiakensis appears to be tolerant of turbidity and may actually prefer it as an escape mechanism from predatory fish which feed mostly by sight. They also seem to prefer aquatic vegetation as well.
Anyways, hopefully this didn’t completely bore you all to death, but I found it pretty interesting. I have no experience with P. kadiakensis, but I know the species I have dealt with are readily gobbled down by just anything that can swallow them. So I am sure they would help build a healthy food chain in any pond.
