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Papua New Guinea


Amano Shrimp

Caridina multidentata (Caridina japonica)



    Considered one of the best algae eating additions for any aquarium. They are highly sought after by hobbyist and make great additions to any tank. I have never had the pleasure of keeping this shrimp so much of this information is gleaned from deferent sources across the Internet. I would greatly appreciate any comments you have on the care and keeping of these fine animals.

Quick stats:

    Listed tank sizes are the minimum
    Size: Up to 2" (5 cm)
    Tank: Any
    Strata: Bottom-middle-top
    PH: 6.5-7.7
    Hardness: Hard and alkaline. dH range: 5.0-20.0°
    Temperature: 59-80°F (15-27°C)


    Order: Decapoda
    Family: Atyidae
    Class: Crustacea
    Genera: Caridina
    Species: japonica

Common name:

    Amano Shrimp, Yamato Shrimp, Yamato numa-ebi

Image gallery:

    Additional species photographs


    Badmans' Forum


    Yamato region in Japan

General Body Form:

    Typical for all shrimp species.


    Body color consists mostly of a light brown opaque color. On the back shell, there is a tan stripe that runs from the head down to its tail. On the shrimp's side flanks, are a series of broken lateral lines that are a reddish-brown in color. The tail also contain two or more black and white dots.

Amano Shrimp


    Amano shrimp are very tolerant when it comes to water conditions. Since they come from swamps and marshes they can also tolerate different levels of salinity. pH is not overly critical and they will adapt to a wide range due to their home water conditions. A well established planted tank is a must as are very sensitive to ammonia/ammonium. Like most invertebrates they are very sensitive to heavy metals - like copper- as it seems to interfere with their molting process which will cause them to die. You must be careful when choosing tankmates for these fish, small peaceful species are the rule. Cichlids and other large fish will simply see them as food and quickly eat them. This shrimp has been known to live up to three years in captivity. Caridina japonica has been known to eat almost every kind of algae known to the aquarist and this is the main reason they are so highly sought after The Amano are not just a cure all for an algae problem as they are finicky when it comes to how much, and of what type of algae to eat. One algae that Amano do not like, is the dreaded black beard algae. Nevertheless, when they are hungry they will gnaw away at some of it. These shrimp are most active at night, but seem to do a decent job during the day as well. Even if there is an abundance of algae in the tank,. In rare cases, Caridina japonica has even been known to eat plants. Along with eating some living plants and algae, Amano will also eat detritus in the form of dead plant leaves and leftover food.


    Found in still and slow-moving marshes and swamps.


    The Amano Shrimp is difficult to breed. I have read that there have only been a few people who have managed to breed these shrimp, and even fewer who have managed to raise the fry. It is believed that the mating season lies in late spring or early summer. If fry are produced, they should be removed from the parents, and should be kept in an aquarium with a sponge filter and plenty of algae to eat.

Breeding links:  
Breeding: Higher Order Decapods Very good basics
Caridina Japonica site. Links to breeding reports with tables
Additional websites:  
Everything About Caridina japonica Much of this information came from this site.
Shrimp - Amano Main Page Another useful site.
Florida Driftwood Small orders Ok and plants as well! Many other inverts as well.


Your comments:


Please remember that the following comments are personal experiences and may or may not apply to your setup. Use them as guide to help better understand your fish, like us all individuals will behave differently under different circumstances.


From: Siksu
Amano Shrimp life span is 10+ years, if taken good care. My little Amano-girl is 11 years old. The other lived 9 years. Shrimp-only tank, Walstad or natural tank method (no water change, heavily planted tank), minimal feeding (once a week or even less), cooler water (18-22 degrees C). It seems such conditions like her :)
From: Jason A.
I have four of these in a 20 gallon brackish (SG = 1.005) tank with two mollies and four guppies. I have had them for about six months now, and I have been very happy with them. They are a very good algae eater for a peaceful brackish setup. I add a couple drops of iodine once a month and have had no molting issues. They mainly eat the same plant-based food that the mollies eat, and also enjoy a chunk on algae wafer once a week.
From: B. Heisenberg
Extremely clever little creatures, they thrive in a single species tank on their own (where you can observe a greater variety of behaviors, absent from the constant threat of predation). Mine live happily on soft sinking community pellets, although they only need to be fed 2-3 times per week when algae growth is present (being kept near a window but NOT in direct sunlight encourages this). These are one of the few species I could recommend for microaquariums (< 10Gal). As mentioned, they tolerate both highs and lows of PH very well. As they are naturally a cooler water species, they do well in unheated tanks (at a room temperature of 21C). They're extremely clean creatures and won't drape your tank with unsightly poop. Because of their sensitivity to ammonia, these shrimp seem to thrive with frequent water changes, even in the presence of a functioning biofilter (I do a 50% water change 1-2 times per week). Water changes also stir up detritus for an extra snack. I would highly recommend that you run their water through a filter to remove heavy metals. Few water conditioners remove all heavy metals. Adding iodine significantly reduces shedding fatalities. I supplement mine with 1 ml reef iodine per 10 gallons per month (or more frequently for large water changes). This small amount makes a huge difference!

From: Roflcopter
I've had my pair of amano shrimp for almost 6 months now. They molt at least once a month, sometimes twice a month. They enjoy most kinds of algae but don't expect a few of them to end your algae troubles. They also enjoy scraps of flake, frozen meaty food, sinking wafers, just about anything. Mine fight over shrimp pellets! Great for any tank as long as they won't be eaten, live comfortably in just about any situation, are easy on the eyes, and fun to watch.
From: Alex
I am new to these shrimp. I bought six for my lidless mini hex, but they all jumped out. In addition to not having a lid, the small space crowded with fish made them extremely jumpy. It's possible they climbed out, but I suspect they jumped. I got a new, lidded, 20 gallon and I am shocked to see that all five new guys are still alive and well after a week. I have five ghost shrimp that hang out on the bottom, but so far the five Amano shrimp are comparatively shy, hanging out mostly in the small baby water hyacinth floating at the top.
From: Diane
I bought 8 Amano shrimp in Feb 2001. I still have 4 buzzing around the tank today (April 2007). Hardy things. I love watching them 'swim' across open water by racing their little legs like cartoon characters. They can shift too ! But if you have a sickly fish in with them, you need to get it into another tank fast else the shrimp will likely finish it off leaving you with nothing but a sad little skeleton.
From: A Taaffe
I bought these for my daughter and they keep her community tank clean. So I bought a few more and kept them in my hospital tank which USED to suffer terribly from algae. Several sick fish later, they are still there and doing a great job
From: Brian
I have been able to breed and raise these little guys in a planted tank for about a year now. Very dense plants, PH is controlled by Co2 to be about 7.0. They are kept with German blue rams so I'm sure I've lost many. Really haven't done anything special to get this result. Amazing clean-up crew!!!
From: Jenny Mallett
Kept these for the last year, pH of 8, nitrate 40ppm. Can't seem to stop them producing eggs. Excellent species to help keep algae levels low, perfect for a community tank.
From: Chris
These little guys have kept my tank very clean and are fairly strong. Here in Japan, the water is very hard and is difficult to maintain steady pH levels. They are true survivors!
From: Lunchbox
As cool as these are, and the ease of caring for them, they are best kept away from many loach species. I had 2 of these shrimp and my blue loaches seemed to have gotten fatter while there was not even a piece of shrimp remains in the tank. Just a lil hint of caution.
From: Einz
Got 2. Very shy when first introduced to tank; kept hiding and even jumped out of tank when I was away. Luckily 1 survived after several minutes outside. Now very outgoing in community tank of tetras and livebearers Sheds old skin after every major water change. Prefers leftovers over algae. Entertaining - must get some more!






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