Once believed to be of the same species, Caridina caerulea and Caridina ensifera are still confused to this day. This guide will outline differences to allow you to differentiate between the two species.
The most obvious difference between the two species is the uropods (tailfan). On C. caerulea both endopods bear a blue streak, whereas C. ensifera has a red-brown blotch on the end of each exopod. This is shown in the image below.
In addition to this, there are very minor differences of morphology, but these are generally too discreet to be of use with live animals.
Distribution and habitat:
Both species are endemic to Lake Poso of Sulawesi, Indonesia. To add complication, both species are widely distributed in the lake, with C. ensifera being slightly more abundant. However, there is a clear difference in their substrate preferences and behaviour. C. ensifera is found on a variety of substrates pelagically, whereas C. caerulea is found on hard substrates (rock, wood) and often remains stationary.
Differentiation is very easily achieved – simply examine the uropods as discussed.
- “The Raffles Bulletin of Zoology 2009 57(2): 343-452
Images of C. caerulea and C. ensifera (for comparison).
Information on C. caerulea and C. ensifera distribution and behaviour.