Origin: Japan; region of Yamato, Yamato River and Southern area of Chiba and Shimane, Korea, Taiwan.
Etymology: japonica; after the country of origin; Japan
First European import: Unk, Caridina Japonica was first used by Takashi Amano in the 1980's, and after that the shrimp were exported world-wide.
Description: See pictures.
Care: Caridina japonica can be kept in almost every community tank, and will help get rid of algae in a tank. With a life expectancy of 2 - 3 years, they are somewhat expensive algae eaters(Compared to Ancistrus which can live for more than 18 years). Still, the presence of a small group of these shrimp can add a little bit extra to the aquarium, and give it a more natural appearance. Frequent waterchanges are recommended, and the shrimp will react to this with a greater activity, and sometimes by shedding. Do not keep these shrimp together with larger fish, as shrimp are the natural food for many fish. Furthermore the shrimp should be able to hide after shedding, until the exoskeleton has hardened again.
Temperature: 20-28 degrees.
Feeding: Algae, if starved sometimes also plants. If they get the chance, tubifex and mosquito larvae are also consumed.
Size: Females 5cm, males 3.5-4.
japonica eggs and the larvae are
extremely small. In nature, the 1mm large larvae float downstream towards
the sea where they grow up until the age of two months. After that they
will return to their freshwater environment to fully grow, and reproduce.
Sexual dimorphism: Females are larger, and usually have their spots on th body in lines. Males have more randomised spots.
Additional: Caridina japonica is very sensitive towards chemicals. Remove the shrimp from the aquarium prior to treatmant of a fish disease. Dead shrimps should also immediately be removed from the tank, since they pollute the water a lot. Despite the fact that the juveniles grow up in brackish water, the shrimp do not respond to salt additions to the aqaurium very well.
In the opinion of the author, Takashi Amano is often misunderstood about Caridina japonica. This shrimp can be replaced by any other algae eating shrimp that can be found locally in your country. If you keep smaller fish, Caridina serrata is a much better solution for the average community tank, considering their life cycly is completed in freshwater. On the other hand, pretty soon populations of Caridina japonica will be established in other parts of the world
Picture references:All pictures: E. Naus
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