Scientific name:
Caridina ensifera¹
Official common name: (accepted by ESA)
Red Morph shrimp
Unofficial synonyms:
Crystal Bee shrimp, Poso Glass shrimp
Etymology:
The species name ensifera (“sword-wielder”) is derived from Latin ensis and ferre, which mean ‘sword’ and ‘to carry’ respectively. This refers to the elongated rostrum of the species.
Origin:
C. ensifera is a lacustrine species endemic to Lake Poso, Sulawesi, Indonesia. Although it is widely distributed in the lake, it does not occur in the connected rivers.¹
The image below show the distribution of the species within the lake.¹
Habitat:
C. ensifera occurs in pelagic swarms and sporadically on various hard and soft substrates. It is the most abundant shrimp species in Lake Poso.¹
Size:
25 – 30 mm
Appearance:
C. ensifera has a very pale blue elongated, slender rostrum. The antennules are a pale red whilst the antennae are clear. The body is yellowish-transparent with white and brown spots.¹ On the dorsal ‘kink’ of the shrimp’s abdomen there are a brown and white band, and each exopod of the tailfan bears a conspicious brown spot.
Behaviour:
C. ensifera is not a timid species, and will be out in full-view foraging for food during the day. It will not often retreat when the tank is approached, unless the change in light intensity is extreme (such as standing in front of a light source). Unusually, this species is rather pelagic- it is often swimming around the aquarium.
Difficulty:
Due to the delicate nature of these shrimp, I recommend only experienced and skilled aquarists attempt to keep this species.
Despite this, I highly recommend C. ensifera to those considering trying lacustrine Sulawesian species as it is a relatively forgiving species.
Feeding:
In addition to the naturally occurring food sources of aquaria, such as algae and biofilms, C. ensifera can be fed on a wide range of foods.
Sexing:
Adult C. ensifera can be sexed with relative ease. Mature females can be identified by their pale yellow ‘saddle’ (or, if absent, their eggs). Following their first parturial moult, female shrimp also often have a deeper and more curved abdomen around the pleopods for carrying eggs as part of their breeding dress.
Reproduction:
Reproduction takes place entirely in freshwater, and offspring immediately assume a benthic lifestyle.
Notes:
This species was originally known as C. ensifera var. ‘Red Morph(e)‘. This is due to the fact Lake Poso is occupied by another similar species which has blue colouration on its body rather than red-brown. This was believed to be an example of polymorphism, and that they were in fact the same species expressing different phenotypes. However, it has since been discovered that they are distinct species. At the time, the other species was known as C. ensifera var. ‘Blue Morph(e)’, and is now officially described as Caridina caerulea. Below is an image showing the morphological differences between the two species.
Sources
- von Rintelen, K. & Cai, Y., (2009). Radiation of endemic species flocks in ancient lakes: systematic revision of the freshwater shrimp Caridina H. Milne Edwards, 1837 (Crustacea: Decapoda: Atyidae) from the ancient lakes Of Sulawesi, Indonesia, with the description of eight new species. Raffles Bulletin of Zoology, 57(2).
Atyidae 