Caridina cantonensis

Updated: Aug 30, 2019

The most abundant and widespread species of freshwater shrimp in Hong Kong. It can be found in almost every unpolluted freshwater habitat, ranging from ponds, hill streams, low land streams, channelized water courses etc.

A typical specimen

Caridina cantonensis exhibit extreme variation in patterns and colours, hence why it's so hard to identify Caridina species. They can range from brown, red, orange, and various shades of green and blue. Additionally, they may have different black spots and stripes.

Specimen with blue morph

Identification: “Caridina cantonensis has a relatively longer rostrum, reaching to the middle of the second segment of the antennular peduncle, or to the end of the third segment […] The finger of the male first pereiopod is longer than the palm in C. cantonensis […] The second pereiopod of C. cantonensis never reaches beyond the scaphocerite […] and the carpus of this leg is only slightly longer than the chela in C. cantonensis […]” “Caridina cantonensis (CL [carapace length] = 6.0–8.0 mm) […]” “[…] life spans of Hong Kong Caridina spp. range from 17 to 22 mo (Yam and Dudgeon [2005]).”


Distinguishing C. serrata between C. cantonensis: A key identification factor are horizontal markings on the 3rd and 6th abdominal segments when the specimens are alive. Additionally C. serrata is the smallest Atyidae in Hong Kong, with adults growing below 200mm, usually no bigger than 150mm, meanwhile C. cantonensis grows up to 350-400mm when mature. Additionally, their rostrums are slightly shorter than most C. cantonensis, however some C. cantonensis also have relatively short rostrums due to genetic factors, so it may not be the most reliable indicator.


Some examples of the natural habitat of C. cantonensis in Hong Kong.


Distribution:

Personal experience: This species is extremely abundant and widespread. It can be found in all sorts of freshwater habitats, as long as there is minimal pollution. Habitats include: lowland streams, hill streams, ponds, channelized watercourses, marshes etc.


Conservation concern:

None.




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© 2019 by Jeffery Chan