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Caridina multidentata
Takashi Amano Shrimp, Yamato Numa Ebi

 Age of Aquariums > Freshwater Fish > Takashi Amano Shrimp - Caridina japonica

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Caridina_japonica_2.jpg (40kb)
Photo Credit: Filipe Oliveira

Name: Caridina multidentata
Size TankpHTemp
Origin: Japan
5 cm 20 L 6.7 24°C


These little guys love aquarium tablet food for bottom dwellers. Be sure no one in your tank is big enough to eat your shrimp! They are fun to watch, but don't freak out when they grow and shed their skins!

Contributed by Koree

We had different experiences with these relentless algae eaters. It seems they suffer with excessive or intensive fertilization, causing massive deaths. In my experience, the female keeps eggs on her bottom side for a period of about 2-3 days, during which the male is supposed to fertilize (inseminate) them. (I unfortunately have never seen any of these eggs become larvae). It seems, by other studies, they will easily reproduce, in dedicated tanks, with no enemies inside (this probably meaning with no one else). One personal tip: Do not feed them!! Especially with bottom fishes' food, which is polluting a good deal. They will soon stop feeding on algae. Ciao!

Contributed by Michele Ralli

My experience with Amano shrimp has been that they are actually pretty tolerant to high nitrate/nitrite levels. A friend put them in his tank three days after it was set up and the gang liked it there and immediately started eating. Oh, eating. Remember never to put your Amanos in a tank with RED alternantheri (green ones are ok). They leave all the plants alone but LOVE eating those for some reason. I blamed my snails until a friend started to have the same problem. You can distract the shrimp with salad or cucumber for a while but eventually they'll be back to munch on them.

BREEDING: The caridina japonica larvae won't survive in a fresh water tank. They need brackish water during the first weeks. In nature, they get carried downstream after hatching. This is obviously impossible in a tank, so you'll just have to improvise. One method is to put the mother into a separate tank until the larvae hatch, then remove her and gradually raise the salinity (your basic cooking salt will do) to about 17 grammes per litre. You can also prepare the nursery tank in advance and just suck the larvae out with a hose. An easy way to do this is to switch off the lights and lure them to one corner of the tank via a flashlight. I've heard yeast is a very good starter food. Once the fry has grown up past the larvae stage you can just put them back in a fresh water tank. They won't mind the change at all. As far as I know, the fertilization of the eggs takes place while they're still inside the ovary. The mother will later carry the eggs around on her belly for protection. You can easily discern them, they have a greyish colour, a bit like caviar. Happy shrimp nursing!

Contributed by Sasha Twen

I've had these shrimps for two years now in my little 100 litre tank. Had 10 from the beginning and now I think I have around 6. The tank is heavily planted and has a little school of pygmy corydoras, a school of rednose tetras, 2 flying foxes, 4 otocinclus and 4 apistogramma trifasciata. Both the apistogrammas and the shrimps are breeding, without any intervention from my behalf. I try to change water every other week and at the same time cut back the plants. But the shrimps are hatching and every now and then I see how 2-3 cm shrimps suddenly appear and grow mature. I try to keep the water rather soft, 28-29°C. So the shrimps are very easy to keep and not so vulnerable at all.

Contributed by Jüri Soomägi

I bought 6 of the supposed "Japanese algae-eating shrimp" about a month after I had set up my tank. I say "supposed" because I have read in a number of places that they are often mislabelled in stores so I am not really sure if they are the right ones or not. And, in any case, they probably have too much access to other food (fallen flakes, pellet residue, spirulina wafers, etc.) that they seem to have little interest in algae. But anyways, around the time that the first one moulted (I thought it was a carcass) I never seemed to be able to account for them all, so I assumed 1 or 2 had died. The ones I could see always seemed to be hiding under the piece of wood on the bottom. Several weeks later I noticed a number that were out and active around the tank, and when I counted them I could see 6 again. I was pleased that they had only been hiding. An hour later I recounted and this time I could see 7! Based on what I've read, I'm very surprised that they have spawned. Generally as a group they are a lot more active now and I usually see most of them on my plants, eating something (I hope its algae!) I find it surprising that I don't see them scavenging the gravel more often, but I am happy they seem to be doing fine and they make an interesting addition to the tank. Strongly recommended.

Contributed by Lon Shaver

In fact they are called Yamato Shrimp. It was first introduced by Takashi Amano and was named after him later on. They are good algae eaters and I've seen them eating hair algae where other algae eaters are rather helpless over it. Since they are usually very hungry and hardworking, I suggest not to keep them in a very "clean" tank as they will attack smaller fish. I've seen it personally and the fish escaped when another Yamato Shrimp also tried to attack it as well. So the two shrimp dragged each other down to the base, a wonderful sight.

Contributed by Aloysius Chong

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