It's still a pretty new study of these shrimps in Taiwan. Although they claim they are the main exporter of this kind, not too much details of the habitat were mentioned...they just catagorized these shrimp a few years back...
According to the records of their national aquatic museum, some university studies and some popular aquatic sites, the following are some translations from what they mentioned in common:
"Cardina Typus are found in the middle reach to lower reach of rivers with bigger rocks, sandy bottom and sparse plantations..."
"...they appear more often near river mouth, for the convenience that they can swim into the sea and deliver the babies..."
"...larvae go through several planktonic stages before metamorphosing into post-larvae (miniature shrimp) and assuming a benthic lifestyle. For this process they need brackish water to full strength saltwater..."
(Mustafa, I borrowed this from you as it was exactly what they described. Hope you don't mind...)
"...they are found mainly in Northeast part of Taiwan, especially in one of the streams. (I am not going to translate the river name as it is useless unless you really want to go there.) The river contains mostly metamorphic rocks, like marble and gneiss. It has relatively faster water flow with deeper stream bed..."
(Found this in the topography of that particular stream.)
"...some hobbyists has been trying to interbreed these shrimps with CRS...reports have been received that eggs were seen being carried, but with a very low survival rate..."
(This one was from a couple popular discussion forums.)
Well, there were some more that were still in debate, so I am not going to put those down...but hope this helps...
