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Yamato numa-ebi(Caridina japonica) FAQ's

 Due to the latest interest in the Japanese swamp shrimp I have decided to
write this mini-FAQ's. My knowledge is based on a few different aquarium
magazine that I have bought here in Japan. My wife, Hiromi, has helped me
with the translation.

 As the name implies Japanese swamp shrimp come from many different swamp
here in Japan. The photographer, artist, author, and aquarist Takashi Amano
was the first one in the world to use this type of shrimp. I believe he
started using them in the early 80's. Now no tank he creates would be
complete without these little guys.

 Numa-ebi(meaning swamp shrimp in Japanese)have been known to eat almost
every kind of algae known to aquarist. But ebi are finicky when it come to
how much of what type to eat. One algae that ebi do not like is the dreaded
black beard algae. These shrimp are most active at night, but seem to do a
decent job during the day too. Even if there is an abundance of algae in the
tank I have observed these shrimp tank fish food from the surface of the
water. In extreme case C. japonica has been known to even eat plants. I have
witnessed them eat my nice lawn of Riccia.

 C. japonica can get to almost 2 inches from nose to tail. Body color
consists mostly of a light brown opaque color. On the back carapace there is
a tan stripe that runs from the head down to its tail. On the shrimps side
flanks are a series of broken lateral line that are a reddish-brown in
color. The tail may also contain two or more black dots.

Care and breeding:
 Japanese swamp shrimp are very tolerant when it come to water types. Since
they come from swamps they can also tolerate different salinity's. Another
parameter that is tolerated is pH. Amano uses them and his pH is about 6.5
with the Aqua Soil. And since C. japonica originates from a swampy/marsh
region with brackish condition I would guess that a pH well above 7 is also
fine. Two thing to point out is that Yamato numa-ebi are very sensitive to
ammonia/ammonium, and heavy metals. Heavy metals will interfere with the
shrimps molting process causing them to die.  Ammonia and ammonium are just
poisonous to all living thing. Other than these simple rule C. japonica
require no other special needs.
 Breeding C. japonica on the other hand is certainly a challenge. According
to Aqua World magazine(March,98)no one has breed them in the confines of an
aquarium. Even the conditions and factors regarding breeding is unknown. It
is speculated that C. japonica might spawn, or what ever crustacean do, in
brackish/saltwater and then return to freshwater or vise-versa. The mating
season seems to be in late Spring or early Summer. I base this on the fact
that I have bought C. japonica during these time with big females holding
eggs. One female held this clutch of eggs for about a week after I bought
her. After that time I did not see the eggs again. I looked in the tank for
baby ebi but found none. This is the same thing that happened to the other
females that were holding eggs.

 I have a question for Mr. Burke Harris(APD V3 #620). Where do you plan on
getting these shrimp that you want to breed? I thought that C. japonica
could not be imported into America and Canada. Please correct me if I am

 And since I am on the topic of Japan and Amano I might as well answer a
question by Kelly Beard(APD V3 #621. Kelly was wondering if Amano tank "are
only constructed to take a pretty picture and then be torn down". The answer
is no. Amano's tanks are all set-up for long term use. It might be true that
he capture the tank during its pinnacle, but none the less they are all
set-up for long term beauty.

 I hope this has helped some of you who have been wondering about Caridina
japonica. Feel free to post more question about Amano and his products. I am
certainly no expert, but I have been using them for four years mostly due to
the high cost of Dupla here.