Amano shrimp on the rock

Amano Shrimp – Detailed Guide: Care, Diet and Breeding

by Michael

Today we will talk about one of the most popular shrimp in aquascaping – Amano shrimp. So in case you want to know how to feed, care, keep and breed this species, this is the right place. I am going to give you all the information about this species including some practical tips on how to breed Amano shrimp successfully in the aquatic hobby.

Caridina Japonica is extremely beneficial to any aquarium simply because they are the best algae eaters. Their larger physical size (two inches) makes them able to eat algae that most other shrimp or small critters cannot. They are also very easy to care for but difficult to breed.

These shrimp are a great choice for an aquarium of any size that has peaceful inhabitants.

A Brief History of Amano Shrimp

Amano shrimp also have alternative names such as Yamato shrimp, Japanese swamp shrimp, Algae-eater shrimp or Caridina multidentata. This species was found in Japan and parts of Korea and Taiwan.

Amano shrimp was introduced to the aquarium hobby by Takashi Amano in the early 1980s (It is also from him where they got the name since 2006) biological control of algae started booming as various forums on the internet were spreading the good news of the fantastic capacity of this particular shrimp to consume algae. When he found out about this amazing ability, he bought several thousands of the shrimps from the local sellers. After that Takashi Amano used them in most of his aquascapes.

Caridina multidentata was previously known to aquarists as Caridina japonica (discovered and described in 1892). Nonetheless, when scientists found studies about Caridina multidentata in 1860 they renamed it to Caridina multidentata in 2006.

Quick notes about Amano Shrimp

Name Amano shrimp
Scientific Name Caridina multidentata
Tank size 10 gallons and more
pH 7.0 – 7.4 (6.5-8.0)
GH 7 – 8 (5 – 15)
KH 2 – 4 (1 – 8)
Temperature 18 – 28°C (64 – 80°F), ideal 24°C (76°F)
TDS 150 – 200 (100 – 400)
Adult size 1.5 – 2″ (3 – 6 cm)
Keeping Easy
Breeding Low order (larvae stage)
Diet Algae eater/omnivore
Temperament Peaceful

Important fact. As you can see these shrimp are the most adaptable shrimp in the aquatic hobby. Amano shrimp can survive almost in any water condition. They are not aggressive in general; unless it is a feeding time then they become voracious and ravenous eaters. They are often seen stealing food from smaller shrimp.

Description and Appearance

Amano shrimp dotsAmano shrimp has a translucent body covered with reddish brown points of ± 0.3 mm on their sides which may look like a broken line of reddish color. Their back has a white stripe that runs from the head to the tail and the eyes are black.

Sex difference

Amano-shrimp female and maleIt is fairly easy to distinguish females from males:

  1. The easiest way to determine the sex of an Amano shrimp is the lowest stripe along the length of the body. Females have dashes almost appearing to be a broken line along that tail. They have the more elongated lower row of dots lining the body. The male shrimp have the same line but it is composed of circular dots evenly spaced apart from each other (a line of separate dots).
  2. In addition, the females are generally much larger in size than the males. They can grow up to 5-6 cm. While the males are usually 3-4cm.
  3. Also, the females will have a saddle (which are her embryonic eggs). (e. egg pouch) and underneath her belly where she keeps the eggs.
  4. Females have significantly longer pleopods on its abdomen and a more rounded abdomen. While the male shrimp have a flat and narrow belly.

Tank conditions (water parameters)

The Amano shrimp care is rather simple and undemanding. They can take a wide range of parameters from cooler water in the mid-sixties all the way up to the mid-80s as well as a wide range of hardness.

Which means that it does not really care about your water parameters as long as the pH, kH, gH, and the temperature are not too extreme just so that you preserve the integrity of their molds and they do not struggle with that. Do that and your Amano shrimp will be living a very happy life.

As we can see, their optimal water parameters are close to Neocaridina shrimps. That makes them closes to ideal tank mates.

There are more active at higher temperatures but this will definitely shorten the lifespan. I would say that these guys are very tough and sturdy. But you will have to keep an eye on your CO2 levels if you are running a high tech tank. As you might know, if CO2 runs out in a high-tech tank you get really bad algae blooms.

You need to acclimate any shrimp before putting them in the tank.

Amano shrimp and Algae

They are an absolute workhorse when it comes to eating algae. Unlike many other types of the shrimp, Amano shrimp eat algae and do not only graze on it. Therefore, in case you have a problem the algae, they are the ones you need to get.

The Diet of Amano shrimp

The diet consists of whatever falls to the bottom of your tank. Amano shrimp are an ultimate cleanup crew and they are perfect for eating up the excess of food. They will forage all day long just as long as you do not have other big fish in your tank intimidating or picking on them or trying to eat them.

Frankly saying, Amano shrimp are not the coolest looking shrimp but we do not get them for their looks we get them for the algae eating potential and these guys just do not stop. They are absolutely relentless towards the algae.

Another great thing about Amano shrimp is that you do not need a lot of them to keep your tank clean. Because of their size (they are usually over five to six centimeters and that is about two inches) Amano shrimps are more efficient compared to other types of the shrimp.

Note: it is strongly recommended that you do not give them a lot of processed foods.

It can have an effect on the algae eating abilities in the long run. The reason for that, if there is something tastier for them to eat other than algae they are going to eat what is easy and tasty. Obviously, it is easier for them to eat processed food than it is to eat algae. Therefore, it would not be a good idea to give them lots of food. I am not saying they will not pick at algae at all. Nevertheless, if you need results the best thing to keep them hungry.

I know that some shrimp breeders do not add Amano shrimp in all their tanks on the permanent basis. They keep them in one tank. So for example, if they have got algae problems in some of their tanks:

  • They simply move decorations or plants over for them to clean for a day or two.
  • They move them to affected tank (have them clean it out) and just move them back to their tank.

Personally, I have a very contradictory feeling about it. I know for sure that professional shrimp breeders usually try not to share even equipment between the tanks. For the safety precautions. Nobody wants to contaminate all their tanks if something goes wrong with one of them.

Interesting fact: depending on their diet, if Amano shrimp keep eating algae they can turn almost a blue-green color over time.

What type of Algae do Amano shrimp eat?

They eat hair algae, brush algae, most types of string algae. These shrimp are one of the few animals that can even eat black beard algae.With them, you will not have to use any chemical stuff. It is slow (depends how many shrimp you have) and yet effective method to control algae by adding them to your aquarium.

Note: the only algae that Amano really struggle with is spot algae that form on the glass or hardscapes.  In this case, I would advise you to get snails as Nerite Snails, Mystery Apple Snail, Malaysian Trumpet Snail etc.

A complete algae fighting force will consists of:

1. Amano shrimp
2. Nerite snail
3. Otocinclus catfish

An experiment – Amano shrimp is the best green algae eater?!

Some time ago there was an experiment – who is the best green algae eater? Amano shrimps, fish and snails were left to graze on the tiles with green algae for a period of time before the tiles were removed and analyzed.

Regardless of how the grazing rate was expressed, the Amano shrimp was the most efficient grazer on the type of substrate offered in the that experiment. When the grazing was expressed as the rate per animal, the Amano shrimp was 7-fold more efficient than the Red cherry shrimp but only 2.4-fold more efficient than the Siamese Algae Eater (SAE).

However, since the Amano shrimp is a relatively large shrimp, some of the difference is caused by the fact that a large animal, in general, consumes more food per time unit as compared to a much smaller animal such as the cherry shrimp. And so, if the grazing rate instead is expressed per gram animal, the Amano shrimp is only 1.8-fold more efficient than the cherry shrimp. For the SAE, it works the other way around as it is bigger than the Amano shrimp, so the difference in grazing pressure is 5.4-fold when expressed per gram animal.

And so, the study was very conclusive in the sense that the Amano shrimp removes much more algal biomass per time unit. The Amano shrimp is the best algal-eater among the candidates. It is the King.

The Behavior of Amano shrimp

Their behavior is non-aggressive. But if you are going to keep them in tanks with other dwarf shrimp, keep in mind, that there are extremely aggressive eaters. They have no problem at running in taking food for themselves pushing other shrimps to the side and walking away. But other than that they are non-aggressive.

Anyway, be cautious if you going to keep them in a small tank with other dwarf shrimp they can (and will) out-compete the other dwarf shrimp for food (except maybe shrimp similar to their size like Ghost shrimp).

The lifespan of Amano shrimp

They also have a pretty decent lifespan from 2 to 5 years in captivity. Some shrimp breeders say that they have Amano shrimp over 6 years old and there is no sign of them slowing down. It takes Amano shrimp 5 months to reach maturity.

Breeding of Amano shrimp

Breeding Amano shrimp is rather hard in captivity but with the determined attitude and patience, it is possible and rewarding. The reason for this is that that they will not complete the life cycle in freshwater. The young shrimp (larvae) require saltwater to grow to metamorphosis and then becomes freshwater shrimp again.

Amano shrimp larvaeIn the wild, Amano shrimp live coastally, where their larvae (or Zoa) are released and swept out to the sea. In the sea, they feed off the algae and plankton until ready to metamorphosize  into their small mature form after about 40 to 50 days. So, after about 6-7 weeks they convert to shrimplets and then migrate back upstream to freshwater.

Therefore, if you want to breed Amano shrimp at home, you will have to replicate this whole process for them. Frankly saying, it is a lot of work but at least we get a much a longer life span than with any other shrimp.

Breeding Amano shrimp in home conditions

The big differences between Amano shrimp and other dwarf shrimp that we keep is their breeding cycle.

Amano shrimp like others shrimp breed in the freshwater the female also molds and releases pheromones in the water for the males to follow. The “scent” will attract male Amano shrimp and they will try to find the female and mate with her. They then breed and the fertilized eggs move down and under the tail, this is where the similarities stop.

Amano shrimp can carry hundreds even thousands of eggs depending on the size and age of the female. For example, the female Cherry shrimp can have 20-55 eggs in general. The incubation period of eggs lasts from 4 to 5 weeks. Then the female will release the eggs. This is where the second big difference comes in.

In order to avoid stress on the female Amano shrimp, the breeding colony should be left in freshwater tank until the female is close to hatching. The point is that brackish water will not hurt adult Amano shrimp but it will kill the eggs.

Preparing Rearing Tank for Amano Larvae

Sea salt productsFirst thing first is the rearing tank. It can be a small one (2.5-gallon or 5-10 liters will be more than enough). Next step is adding sea salt. Unfortunately, there is no unanimous opinion about the correct level of salt added to the water. In most cases, according to experienced shrimp breeders, you need 32-35 PPT for the Amano larvae. Higher (more than 40) or lower (less than 25) levels of salt will kill them.

Set the light 24/7 for algae growth.

Optional but advisable: Add Tetraselmis or any seaweed. It will naturally provide needed nutrition for your larvae.

Now your tank is ready for larvae.

Note 1: There are a lot of “so-called” sea salt on the market, which is not the sea salt at all. Go to any aquaristic shop and buy the real Sea Salt (link to check the price on Amazon) there.

hydrometer to measure the salinity in the aquariumNote 2: you will have to purchase a hydrometer (link to check the price on Amazon) to measure the salinity. In addition, you will also need to have an airstone with the reduced flow for circulation (or bare airline tube). Otherwise, the flow of water will lift the larvae upwards, where they can stick to the bacterial film on the surface of the water and die. Temperature 21-24C.

Important: some people make a simple mistake, which can kill Amano larvae. They provide 24 hours of light but they do not do it in advance. As a result, algae do not have time to grow and larvae die without enough food.

Hatching day

When you can see the eyes of developing embryos through the eggshell, then the eggs will hatch within a few days.

There are two options here:

  1. You can prepare another cup (4-5 liters) for the berried female. You can use freshwater from the main tank so it will not be stressful to her. This is where the eggs will hatch. So, when the female is about to hatch, you need to move her to this cup. After hatching, return the female Amano Shrimp to the main tank to avoid her eating her own young. The female will molt and almost immediately starts producing another batch of eggs.
  2. If you do not want to mess with the separate cup for the female. Leave everything as it is. Of course, it will be a little bit more difficult to catch all larvae in the big tank (this is the goal of the first option) but it is possible anyway. (Tip: People have noticed that once you do a water change, the females release their eggs and they have baby shrimp).

Important: In both cases, the trick with Amano shrimp is that you have to get the babies out of fresh water and put them into saltwater as fast as you can. Remember that the larvae must go into brackish water within 48 hours or they will all die.

So, how can you do that?

Tip: Light attracts Amano larvae. So, lure them to a spot with a flashlight or adjustable spot desk lamp to the corner of the tank. Then use a turkey baster or a big syringe to catch the Amano larvae. They are tiny (~1,5mm length) and you will suck them in easily.

Rearing Amano Larvae in Brackish Water

Minor larvae can raise and grow only in brackish water. Provide them with clean water and 24 hours of light. The 24 hours of light produces enough algae for the larvae to survive off.

Days 1-20

When the tiny eggs hatch, the first stage is not just tiny bottom-dwelling baby shrimps but instead pelagic larvae. And these larvae need a period in salt water to complete the ontogenesis before they become true baby Amano shrimps and the latter step prevents easy breeding.

Feeding: besides algae, you can feed them with a single spirulina flake (fish food) and dry yeast. Crush it into powder. One single flake provides thousands of tine food particles for the larvae to munch on. Ideally, you need to feed them every 5 hours at regular intervals.

Phytoplankton Tetraselmis for aquariumSome examples of the diet:
1. Algae
2. Liquizell
3. Golden Pearls (5-50 Microns)
4. Spirulina Powder (mixed with water)
5. Mosura Shrimpton
6. Phytoplankton (link to check the price on Amazon) 
Tetraselmis
– Dunalliela Salina
Nannochloropsis

Some breeders do not exactly feed the Tetraselmis to the zoeas.  Instead, they drop the zoeas directly into the algal culture.  As a result, the shrimp larvae get to live in a never-ending algae buffet, and their wastes are immediately reprocessed by the remaining algae into more food.  Nitrate and ammonia never have a chance to accumulate and, as long as you keep the lights and air turned on, oxygen is abundant.

Be careful, do not overfeed them! The larvae do not need an overabundance of plankton or to have the water green with algae and phytoplankton. It can cause dangerous water chemistry.
Water changes every 2-3 days (10-20%). Keep using the trick with the light to move any larvae over to one side, siphon from the other side, it helps to reduce losses.

Tip # 1: Do not forget to check the water level. Keep it at optimal 32-35 PPT.
Tip # 2: If you can barely see the opposite side of the tank due to phytoplankton, it would be better to do a 50% change, using method discussed earlier.

Important: Over some time, a bacterial film will form on the surface. If you do not remove it (at least manually) some larvae can stick to it and die.
Interesting fact: First few week larvae swim in a heads-down position. They are almost transparent and barely visible.

Days 21-30

You can notice a slight transformation. It means that from days 25-30 you can start lowering salinity to 15-25ppt. Just do the water change and add some fresh water.
Feeding: the same. If you see that there are a lot of algae (because of 24/7 light) it is possible to cut spirulina flakes or any other additional sources of food.

Days 40-45

Pay attention to the larvae.  At this stage, Amano Shrimp larvae can complete transformation (metamorphosis) into actual Amano shrimp. From this moment, they are tiny copies of adult shrimp. It means that they cannot tolerate elevated salinity level anymore.

Another sign is swimming only forward non-stop (Larvae can swim in all directions). If you see that they are swimming like crazy all the time, it means that they are ready to go into your main aquarium. In nature, this behavior says that they are trying to swim out of the saltwater upstream into the freshwater.

Tip:  do not do any sudden transitions from brackish water to freshwater. Replace half of the brackish water with your aquarium water for 1 day. Let them accustom a little bit to the new water conditions. After that, drain the water in the bowl down to the bottom. So it will be easier to put them into the main tank.

Conclusion

Most hobbyists will gladly keep them but they will never breed them. Unless they are doing it as a personal challenge to prove their skill sets, or out of curiosity. Amano shrimp are pretty cheap, so there is no reason to do it for monetary value. It only works on a big scale.

These shrimp will be your vanguard forces against algae. They are amazing, never stop and never tired.
In addition, Amano shrimp do not cross-breed with other shrimp you might keep. So, we have one less worry about.

Some frequently asked questions about Amano shrimp

What is the minimal Tank size Do Amano shrimp Need?

Amano shrimp are the biggest dwarf shrimp. Due to the size, it is advisable to keep them in at least a 10 gallon aquarium. This size of the tank will be enough to keep 5-6 shrimp without overstocking them.

How Many Amano Shrimp per Gallon?

This is not a science and there is no exact answer. That is why according to the mighty rule of thumb you need to follow the ratio 1 Amano shrimp per 2 gallons (~7-10 liters). Of course, you will have to take into consideration what else you have in your tank. Note: Takashi Amano himself said that 1 Amano shrimp per 1 liter is good enough but … well, with all respect, I disagree a little bit.

How many Amano shrimp do I need?

In nature, Amano shrimp live in huge colonies (hundreds of shrimp). Of course, not everybody can and want to have that many Amano shrimp in the tanks. Nevertheless, in terms of experience from many shrimp breeders, it is reasonable to have at least 6-10 shrimp. The more shrimp you have the less stressful and shy they are.

My Amano Shrimp Jump out of My Tank

Unfortunately, it is not a rare incident. They do not mind climbing out of the aquarium, especially, when they do not like water parameters. Also, sometimes when the shrimp are swimming so hard they can jump out the aquarium. Thus, you need to use a lid to cover your tank.

Tip: however, in case you have a rimless tank it would be in your interests to drop the water level by a few centimeters.

Why do females lose their eggs?

The females can start throwing off the unfertilized eggs. It may happen when pheromones of other females in the tank superimpose on each other. As a result, males cannot find the female. Other reasons are the stress, bad water parameters or big water changes (more than 70%).

My Amano shrimp are green in color is that normal?

Shrimp Ellobiopsidae diseaseIf you have algae in your aquarium and Amano shrimp do not show any signs of stress , well, it is normal. Algae diet can have a certain impact on their coloration. If you see the picture like this, I am sorry, but they have Ellobiopsidae. This is a disease. 

Would the Amano shrimps go after my red cherry shrimps if they get hungry?

Unlikely, but if they were starving to death probably. Amano shrimp are significantly bigger than cherry shrimp and can easily overpower it. Nonetheless, they are not hunters, they are scavengers. I would say that it is the same story and chances as with Assassin snail.

Will they eat my plants?

No, they are algae and detrivore eaters. They will not harm the plant. People usually confuse grazing on with eating the plant.

Can Copper Kill Amano shrimp?

Yes, it can. All aquatic invertebrates are susceptible to the copper. It is toxic to all dwarf shrimp. Check fertilization and medication beforehand. They can contain elevated levels of copper. 

You can read more about “How Copper Affects Dwarf Shrimp” right here.

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