The Amano shrimp ( Caridina multidentata ), also known as Yamato shrimp or Japanese algae shrimp, is a popular freshwater aquarium inhabitant renowned for its algae-eating capabilities and peaceful nature. Originating from East Asia, specifically Japan, Taiwan, and parts of China, these shrimp were first discovered in the streams and rivers of Japan, where they inhabit clean, freshwater environments. Their introduction to the aquarium trade is largely thanks to Takashi Amano’s work in the aquascaping community, where they became a staple in aquariums for controlling algae growth and creating natural, balanced environments.
This article delves into the comprehensive care, dietary needs, and breeding aspects of Amano shrimp, offering valuable insights for both beginner and experienced aquarists.
Natural Habitat and Background
In their natural habitat, Amano shrimp can be found in larger river systems, particularly the upper reaches. In the wild, Amano shrimp are typically found in slow-moving rivers, streams, and ponds with dense vegetation and plenty of natural hiding spots. These habitats provide the shrimp with abundant food sources such as algae, detritus, and biofilm.
Did you know? The IUCN Red List considers Caridina multidentata to be a species of Least Concern. This means it's not currently threatened in the wild.
Introduction to the Aquarium Hobby
Often, not much is known about how a fish or invertebrate species was first introduced into the aquarium trade. Today's subject is an exception, and it's a fun little story! The Amano shrimp has been a staple in the aquarium hobby ever since it was first introduced on a large scale by legendary aquascaper and photographer Takashi Amano. According to Practical Fishkeeping Magazine, Amano promptly asked his regular supplier to gather a few thousand(!) of these wonder shrimp for him. The supplier in question hadn't had much luck selling the species before and was therefore not enthusiastic about the venture, but Amano insisted. His use of what is now known as the Amano shrimp in some of his most legendary aquascapes meant its popularity quickly soared around the globe.
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Appearance and Distinguishing Features
Its appearance isn't what made the Amano shrimp famous: this shrimp is pretty plain-looking. Transparent with a pattern of dark brown to black dots and dashes along its sides, it grows to a maximum size of around 2" (5 cm), although they can sometimes reach up to 2.5 inches (6.5 cm) under optimal conditions, making it a good bit larger than common dwarf shrimp like Neocaridina. When purchasing from pet stores or online, it's common to receive shrimp around 1 inch in size.
Another characteristic that sets Amanos apart from most other shrimp kept in the aquarium is that they start their lives as larvae rather than as tiny copies of their parents.
Did you know? Amano shrimp were scientifically known as Caridina japonica until a taxonomic revision in 2006. Although they're now called Caridina multidentata, you may still find them for sale under their old name.
Sexual Dimorphism
Amano shrimp ( Caridina multidentata ) exhibit sexual dimorphism, meaning there are physical differences between males and females. Despite these differences, the distinction between males and females can be subtle, especially when they are not carrying eggs.
It's pretty easy to tell male and female Amano shrimp apart. First off, if you keep a larger group, you'll notice that the males are significantly smaller than their female counterparts. The lowest line of dots on their body is more separated (it looks more like a broken line in females) and the part of the exoskeleton covering their back legs is straight rather than curved. Lastly, you may see a yellowish to greenish organ behind the females' heads-this is called the saddle, and it contains undeveloped eggs.
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Aquarium Setup and Water Parameters
If you'd like to keep Amano shrimp, you should go for an aquarium with a volume of at least 5 gallons (10+ gallons would be ideal). Amano Shrimp can be kept in tanks of nearly any size as long as the regular rules of fish count are followed. Be mindful not to overstock. The tank should be filtered and, unless the ambient temperature is always stable, heated with a thermostat heater. As we've discussed in the section on habitat, Amano shrimp originally hail from a river-type biotope. Luckily for us aquarists, though, they're very versatile and can thrive in almost any type of aquarium. Just make sure there's plenty of cover in the form of rocks, driftwood, live plants, and shrimp flats. They are best kept in a well-established tank with plenty of live plants, rocks, and hiding spaces (such as moss, driftwood, and caves). They enjoy a tank with natural elements to feel secure. The substrate should be fine, nutrient-rich gravel, sand, or aquasoil.
Ideal Water Conditions
One of the reasons Amano shrimp make such a good choice for the beginning aquarist is that they're not fussy at all about water parameters. As long as your tank is fully cycled, your Amanos can survive in a wide range of pH values, temperatures, and hardness levels. The most important thing is stability, rather than hitting exactly the right values. The ideal water temperature for Amano shrimp is between 68°F to 78°F (20°C to 26°C). They prefer stable water temperatures and should not be exposed to drastic fluctuations. They are hardy and can tolerate water temperatures ranging from 71°F to 82°F (22°C - 28°C), though an optimal temperature of around 75°F (24°C) is recommended. The water parameters should be closely monitored, with a pH of 6.5-7.5, a hardness of 4-8 dGH (moderately soft to slightly hard water), and a KH (carbonated hardness) between 1-4 dKH. Both ammonia and nitrites should be at 0 ppm at all times, and nitrates should remain below 20 ppm. A gentle filtration system is important to maintain good water quality, as strong currents are not suitable for Amano shrimp.
Acclimation and Water Changes
For the best results, acclimate your Amano shrimp carefully when you introduce them into a new tank. When introducing Amano shrimp to a new tank, acclimate them slowly by floating their bag in the aquarium and gradually adding small amounts of tank water to the bag over 30 minutes to an hour. Regular water changes are essential for maintaining a healthy environment for Amano shrimp. A 20-30% water change each week is ideal, but this can vary depending on the size of the tank and the bioload. Amano shrimp are sensitive to poor water quality, particularly ammonia, nitrites, and chlorine. Always treat tap water with a water conditioner before adding it to the tank. Amano Shrimp seem to like water that is on the hard side, well circulated and with a current that is moderately moving.
Tank Mates and Social Behavior
Although they're pretty aggressive eaters as far as shrimp go, Amano shrimp are generally considered peaceful. Pick Tank Mates Carefully: Amano Shrimp tank mates should not include aggressive fish such as Goldfish, cichlids or other roughens, or the likes of a aquarium crayfish, Tangerine Lobsters, or Hammers Cobalt Blue Lobsters.
They make a good addition to dwarf shrimp tanks, like with red cherry shrimp or crystal reds. You can also add them to your peaceful community aquarium, provided there are no fish present that are large enough to fit the shrimp into their mouth (because if they can, they will). Amano shrimp are peaceful and can be kept with other non-aggressive species such as small fish (e.g., neon tetras, guppies, or rasboras). They may also coexist with other invertebrates like snails and other shrimp species. However, they should not be kept with larger or aggressive fish, as these may prey on the shrimp. Amano Shrimp tank mates can include others of their kind, as well as most small to midsize non-aggressive community tank inhabitants including Otocinclus Catfish and Cory Catfish. Freshwater snails can include the likes of Nerite Snails, Malaysian Trumpet Snails, Mystery Snails, Golden Inca Snails, Ivory Snails, Rabbit Snails, Japanese Trapdoor Snails, Assassin Snails and Ramshorn Snails. Other tank mates can include other freshwater shrimp like Bamboo Shrimp, Vampire Shrimp, Red Cherry Shrimp and Ghost Shrimp provided the Amanos are larger. In a tank with other shrimp species, care should be taken to avoid competition for food. Amano shrimp are also known to crossbreed with other Caridina species, which can result in hybrid offspring.
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As for the Amanos themselves, we recommend getting at least a few. A 5-gallon tank can sustain a trio, and you can add another shrimp for every gallon after that. Amano Shrimp like living in both small and larger groups, and do well living with their own kind. They are comfortable being both out in the open and exploring little hiding places, and they like anything in a tank that they can pick on. Their bioload is almost zero, so there really isn't much of a limit on how many you can keep.
Diet and Feeding Habits
The Amano shrimp is easy to feed. The species is omnivorous and will eat pretty much anything, but is often referred to as "Algae Eating Shrimp" due to its reputation for being an excellent aquarium cleaner. That's why it's in our top 3 of best algae eating shrimp! Amano shrimp enjoy feeding on many types of algae. They even go for some that other shrimp won't touch, such as black beard algae. Amano shrimp ( Caridina multidentata ) are renowned for their exceptional ability to control algae in freshwater aquariums.
Amano shrimp feed on algae by using their small, specialized mouthparts to scrape algae off surfaces. They spend a significant portion of their time grazing on rocks, substrate, aquarium glass, and plant leaves, eating algae and biofilm.
While Amano shrimp are efficient algae eaters, they may not be able to eliminate large algae blooms entirely. For heavy algae infestations, you might still need to address the root causes, such as poor lighting, excessive nutrients, or insufficient filtration. Amano shrimp are most effective when the tank has a healthy balance of algae, and their grazing keeps it under control.
Aside from algae, aquarium plants provide microorganisms and continuously shed edible plant matter, which the Amano shrimp consume, preventing it from accumulating on the substrate. Caridina Multidentata will eat the dead plant matter that would otherwise accumulate on the bottom. So its best not to keep Amano Shrimp in a tank that is “too clean”. Aquariums that are “too clean” may not have enough natural food sources to support the shrimp. Although we recommend supplemental feeding with shrimp-specific foods or blanched veggies for small or very clean tanks, it may not be necessary in larger and "wilder" set-ups.
Supplemental Feeding
As mentioned above, Amano Shrimp have quite the appetite for algae, but they will also eat leftover fish food and detritus on the floor of your aquarium. If there is not a lot of algae in your tank, they can be fed a variety of foods to supplement their diet, including shrimp pellets, fish flakes, algae wafers, bloodworms, and blanched vegetables (such as zucchini or spinach). Fish flakes, shrimp pellets and algae wafers can be either put into the tank whole or ground up into smaller pieces. If pellets are added whole, Amano Shrimp will be quick to grab a pellet. And Amano Shrimp will steal pellets from other shrimp. If pellets are ground up and the fine particles poured in, it creates a cloud of food that may send the shrimp into a feeding frenzy. Amano shrimp are omnivores, primarily feeding on algae, biofilm, and detritus in the tank. Supplement their diet with high-quality algae wafers designed for shrimp or other invertebrates. You can also offer blanched vegetables like spinach, zucchini, and cucumber to provide extra nutrients. Feeding should occur once or twice a day. Offer small amounts of food and remove any uneaten food after a few hours to maintain water quality. To ensure they receive the proper nutrition, it’s a good idea to feed them regularly with high-quality shrimp pellets, blanched vegetables like spinach or zucchini, and Spirulina-based foods. Feeding Schedule: Offer supplemental food once or twice a week in addition to their scavenging habits. Common Mistake: Overfeeding can lead to water pollution and health issues for both shrimp and fish.
Amano shrimp have a unique approach to eating compared to other shrimp. As soon as a food pellet is dropped into the aquarium, they quickly sense it and immediately gather the food.
Amano Shrimp feeding also may include eating dead fish and snails. These should be removed from the tank as soon as possible to avoid Ammonia spikes. Interestingly, Amano Shrimp seem particularly fond of Marimo Moss Balls. Caridina Multidentata do not eat moss balls per se. Instead they like to climb on the moss ball, picking off little bits of food as they travel across the surface. Amano Shrimp also like tanks with a sponge filter.
We personally like to feed them foods with added calcium - like shrimp foods and Hikari Crab Cuisine - to make sure they can successfully molt. Don’t be alarmed if you see a molted exoskeleton.
Algae Control
Amano shrimp are one of the best “natural” solutions for helping to keep algae at bay while you balance the lighting and nutrients in your planted tank. They are widely available, reasonably priced, and super hardy. If you’re having some algae problems in your aquarium, we really recommend you give them a try. Algae can become a natural problem in any aquarium. If you have the wrong amount of light and nutrients, this unsightly issue can quickly take over in no time. While there are many methods for getting algae under control, having an algae eater in the tank is one of the easiest, safest, and most efficient approaches.
Here are some algae types that Amano Shrimp help control:
- Green Hair Algae: This is one of the most common algae types that Amano shrimp help control.
- Brown Diatom Algae: Amano shrimp can also help clean up brown diatom algae, which often forms a dusty brown coating on aquarium surfaces.
- Soft Algae: They are adept at eating soft algae, which forms a slimy coating on surfaces such as leaves and decorations.
It’s a misconception that they will “eat away” algae problems in a tank. Algae problems in a tank are related to water conditions and lighting issues. If an aquarium has algae problems, adding a half dozen Amano Shrimp is not the best solution. Instead, determining the root cause (or causes) of the algae problem is necessary. A good example of this is a common aquarium algae: Green Spot Algae. This form of algae is green, hard, and grows in clusters of little circles on solid surfaces in a tank. So think of Amano Shrimp not just as algae eating shrimp, but instead as great scavengers constantly astir, working tirelessly as industrious tank cleaners, feeding on otherwise uneaten bits of food and picking at particles of edible material too small to be seen by the naked eye.
Breeding Amano Shrimp
Breeding Amano shrimp is considered possible, but highly challenging. Breeding Amano shrimp in a home aquarium can be difficult, as their larvae require brackish water to develop. While Amano shrimp can breed in freshwater, the larvae do not survive without a transition to brackish water, making successful breeding uncommon in most home aquariums.
This is due to the fact that these are lower-order shrimp, meaning they pass through a larval stage rather than hatching as tiny copies of the adults. The larvae require brackish water conditions. After metamorphosis, however, they need to be gradually transitioned from brackish to freshwater. Even if you receive a pregnant female Amano shrimp, you will likely find that her eggs never produce offspring. Brackish water (which is a mix of fresh water and sea water and thereby has more salinity than fresh water, but less than sea water) is required for Amano shrimp to reproduce successfully.
After mating, the female shrimp carries the developing eggs under her pleopods for 4-6 weeks until they hatch. You can transfer her to a separate hatching container in the last week. Then, when the eggs hatch, you can use the light from a torch to attract the larvae to the water surface so you can siphon them out. You have 4-7 days to move the larvae to saltwater, although it's best to just do it immediately.
Tip: If after reading all this you still have no idea how to breed your Amano shrimp, that's not surprising, as it really is quite complicated. That's why we also created a dedicated full Amano shrimp breeding guide.
The adults show clear sexual dimorphism: females are larger, reaching 2-2.4 inches (5-6 cm), while males only grow up to 1.2 inches (3 cm). The challenge in breeding comes after the eggs are laid. Amano shrimp larvae require brackish water to survive.
- Breeding Tank Setup: Set up a separate 20-liter (5.28 US gallons) tank with no substrate and a sponge filter for gentle water movement.
- Larval Feeding: Larvae feed exclusively on phytoplankton, which can be cultured in a separate tank exposed to sunlight.
- Transitioning to Freshwater: After around six weeks, the larvae undergo metamorphosis into juvenile shrimp.
- Brackish Water Maintenance: Maintaining the correct salinity is crucial.
Expert Tip: Regularly monitor water parameters in the breeding tank to ensure optimal conditions for larval development.
Health and Common Issues
Amano shrimp ( Caridina multidentata ) are generally hardy and resilient in a well-maintained aquarium, but like any aquatic species, they can be susceptible to certain health issues and stressors if the tank environment is not optimal.
Water Quality Issues
- Amano shrimp are highly sensitive to water quality, and poor water conditions are one of the most common causes of stress, disease, or death.
- Ammonia, Nitrites, and Nitrates: Elevated levels of ammonia or nitrites are toxic to shrimp, and even slightly high levels can cause severe harm or death. Amano shrimp are also sensitive to high nitrate levels, which can stress them over time. To prevent this, perform regular water changes (about 20-30% weekly), and use a good filtration system to maintain low levels of ammonia and nitrites.
- Chlorine/Chloramine: Tap water often contains chlorine or chloramine, which can be harmful to shrimp.
- pH and Hardness: Sudden shifts in pH or water hardness (GH) can cause stress. Amano shrimp thrive in water with a slightly acidic to neutral pH (6.5-7.5) and a moderate hardness (4-8 dGH).
Molting Problems
- Molting, or shedding the exoskeleton, is a natural process for Amano shrimp as they grow.
- Incomplete Molt: If the shrimp cannot fully molt, it may become stuck in its old shell, which can lead to injury or death. This can happen if the shrimp is stressed, or if there’s a lack of calcium in the water or diet.
- Molting Stress: Shrimp are very vulnerable during molting. They may hide during this time to avoid predators, and sometimes other tankmates may take advantage of this vulnerability. Molting occurs about once every 1.5 months. To make sure your Amano shrimp can molt successfully, be sure to feed a diet rich in calcium. A calcium deficiency can lead to issues during molting.
Stress Factors
- Amano shrimp are peaceful creatures, but they can become stressed due to various factors.
- Incompatible Tankmates: While Amano shrimp are generally peaceful, they can be harassed or preyed upon by aggressive fish, larger fish, or aggressive shrimp species. Tankmates like cichlids, bettas, and larger fish with big mouths may pose a threat.
- Water Temperature Fluctuations: Rapid temperature changes can cause stress, so it’s important to keep the tank temperature stable, ideally between 68°F to 78°F (20°C to 26°C).
- Crowded Environments: Overcrowding can lead to stress and competition for food. Amano shrimp generally do well in small groups, but a tank with too many shrimp may cause territorial or food-related stress.
Diseases and Infections
- * White Spot Disease (Ich): This is a common parasitic infection in freshwater aquariums, characterized by white cysts on the body and gills of shrimp. Although Amano shrimp can sometimes be carriers of Ich, they are more often affected by it when water quality is poor. To prevent Ich, maintain a stable environment with clean, well-filtered water.
- Bacterial Infections: Poor water quality or injury during molting can lead to bacterial infections. Infected shrimp may show signs like discoloration, lethargy, or soft, slimy bodies. Keeping water parameters within the proper range and providing a stress-free environment can help prevent infections.
- Fungal Infections: Fungal infections are rare but can affect shrimp that are weakened due to other health problems. Infected shrimp may develop fuzzy, cotton-like growths on their bodies.
- Parasites: Shrimp can be susceptible to parasites like shrimp mites.
Dietary Issues
- Amano shrimp are scavengers and rely on algae, detritus, and biofilm for food. However, a varied diet is essential to keep them healthy.
- Algae Dependence: While Amano shrimp are excellent algae eaters, they may not have enough algae in a newly established tank.
Overfeeding
- Feeding Amano shrimp too much can lead to water pollution and deteriorating water quality, which, in turn, can cause stress and health problems.
- Food Waste: Provide small amounts of food and remove uneaten portions after a few hours.
By addressing these common conditions, maintaining proper water parameters, providing a balanced diet, and offering a stress-free, clean environment, you can help ensure your Amano shrimp stay healthy and thrive in your aquarium. To avoid introducing diseases or parasites, it’s best to quarantine new shrimp for a week before adding them to your main tank. Lastly, avoid handling Amano shrimp directly. They are delicate creatures and can be injured easily.
What to Do If an Amano Shrimp Dies
A dead Amano shrimp will turn a bright orange-red color and, if left in the tank long enough, will turn white. When an Amano Shrimp dies it will turn bright orange. Other shrimp or snails may start eating its shell to ingest its minerals. It is normal to see other shrimp and snails feeding on the dead shrimp's shell, as shrimp are opportunistic feeders and consume the shell for its rich mineral content. You can remove the dead shrimp immediately or wait until the other shrimp stop showing interest in the carcass. Don't leave it too long, or it may cause an ammonia spike in small aquariums.
If yours died shortly after buying it, you may not have acclimated it properly. You should check the water parameters in your tank to ensure they're still in order, because this is not normal.
Planted Aquariums and Amano Shrimp
Amano shrimp thrive in planted aquariums because they provide both shelter and a source of food. Amano shrimp are typically gentle on plants. They do not tend to damage or uproot plants, unlike some fish species that can be more destructive. However, there are a few considerations to keep in mind. If food is scarce or if they are particularly hungry, Amano shrimp may occasionally nibble on soft or delicate plant leaves. While this is not a major issue, it’s important to ensure that their diet is well-supplemented with algae wafers, vegetables, or other foods to prevent them from grazing on the plants. Additionally, when Amano shrimp molt (shed their exoskeleton), they may leave their old shells on plant leaves, which should be removed to maintain water quality.
Here are some suitable plant species for Amano shrimp tanks:
- Java Moss (Taxiphyllum barbieri): This plant provides a perfect environment for Amano shrimp to forage.
- Anubias: A hardy, slow-growing plant with thick leaves that Amano shrimp will find appealing for grazing.
Purchasing Amano Shrimp
You should be able to find these shrimp at any chain pet store, mom-and-pop aquarium store, and online. The Shrimp Farm sells Amano shrimp! Have your shrimp shipped directly to your doorstep with live arrival guarantee today.
Here are some online suppliers where you can purchase Amano shrimp. Please note that online shops may cease to exist or change over time, so we also recommend using search engines for updated options.
Before buying, make sure the Amano has all of its body parts. Look especially closely for its eyes and antennae pairs.
Lifespan
Amano shrimp lifespan is pretty decent: usually about 3-5 years. We've had Amanos live longer than that, though! An Amano Shrimp lifespan is between two and three years.