Updated C. caerulea

Updated the C. caerulea page, including some new images showing differences between the sexes and differences between C. caerulea and C. ensifera!

Synonyms:

Blue Leg shrimp, Caridina ensifera ‘Blue’, Blue Poso shrimp

Scientific name:

Caridina caerulea

Etymology:

The species name caerulea (“blue”) is derived from Latin caeruleus, which means ‘blue’. This refers to the general colouration of the shrimp.

The former 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.

Size:

25 – 30 mm

My water parameters:

Temperature 29°C
pH 7,5
General hardness
Carbonate hardness
Total dissolved solids 262 ppm
Electrical conductivity 570 µS

Appearance:

C. caerulea is a understated and beautiful species. Although they may appear dull in appearance next to the many striking lacustrine species from Sulawesi, a closer look shows it too has strong colours. Its rostrum, pereiopods and uropods have a blue colouration, whereas its antennae and antennules are a vibrant red. C. caerulea also has a habit of changing its body colour, ranging from steel blue to pink-orange.

Behaviour:

Unlike most lacustrine Sulawesian species, C. caerulea 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 infront of a light source).

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. caerulea to those considering trying lacustrine Sulawesian species as it is a relatively forgiving species. I have found that it will tolerate and breed within a wide range of alkaline conditions unlike most species of the Sulawesian lakes. However, it is unlikely that the delicate shrimplets will survive unless provided the optimum parameters.

Origin:

C. caerulea is a lacustrine species endemic to Lake Poso, Sulawesi, Indonesia. The image below show the distribution of the species within the lake.

Feeding:

In addition to the naturally occurring food sources of aquaria, such as algae and biofilms, C. caerulea can be fed on a wide range of foods. My colony accept:

  • AquarLiam inverteBites
  • Fish flake
  • Catfish pellets
  • Spirulina
  • Boiled carrot, boiled cucumber
  • Frozen bloodworm
  • Katappa leaves

Sexing:

Sexing C. caerulea is generally quite easy. The most obvious sign in adult shrimp is the egg saddle present in the female shrimp, which is usually green or bright yellow. Female shrimp also often have a deeper and more curved abdomen around the pleopods for carrying eggs.

Reproduction:

The reproduction of C. caerulea takes place entirely in freshwater, and involves no larval stages. The eggs take about 18-20 days to hatch. Juvenile C. caerulea immediately assume a benthic lifestyle after hatching. Rather than stimulating breeding, it is the raising of the offspring that is the challenge. In the optimum conditions, this can be achieved with very little effort. However, in less suitable conditions, the juveniles will literally vanish. I assume the juveniles have difficulty moulting, resulting in death. The juveniles are also physically fragile and will not endure currents (these shrimp are lacustrine; they are from lakes where the water is still), so refrain from using more filters with power-heads or similar.

Juveniles will graze on biofilm and algae in the aquarium. They tend to enjoy grazing on the aquarium glass where these thrive.

Notes:

This species was originally known as C. ensifera var. ‘Blue Morphe‘. This is due to the fact Lake Poso is occupied by another similar species which has brown-red colouration on its body rather than blue. 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. ‘Red Morphe’, and is now officially described as Caridina ensifera.

Sources:

  • “The Raffles Bulletin of Zoology 2009 57(2): 343-452
    K. Rintelen
    Y. Cai”:

Image of C. caerulea distribution.
Images of C. caerulea and C. ensifera (for comparison).

  • “www.equator.web.fc2.com”:

Image of C. caerulea in natural habitat.

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