Amano shrimp (Caridina multidentata), also known as Yamato shrimp or Japanese algae shrimp, originate from East Asia, specifically Japan, Taiwan, and parts of China. They were first discovered in the streams and rivers of Japan, where they inhabit clean, freshwater environments. The species is named after the Japanese aquatic biologist, Takashi Amano, who popularized the shrimp in the aquarium hobby due to their algae-eating abilities and peaceful nature.

 

Lifespan	2-3 years
Origin	China, Japan, Taiwan
Adult Size	63.5mm/2.5 inch
Tank Size	10-20 L
Alias	Japanese Algae Eaterplant Yamato Japanese Swamp Shrimp Japonica Amano
Scientific Name	Caridina multidentata
Parameters	GH: 2 - 10 KH: 2 - 8 PH: 6.5 - 7.8 Temp: 6.8 - 7.5 (No heater)

 

Amano Shrimp - An Introduction

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. In their native environment, they play a crucial role in maintaining the balance of these ecosystems by consuming algae and organic material.

The shrimp's introduction to the aquarium trade was 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. While their native range is limited to East Asia, Amano shrimp are now found in aquariums worldwide. To ensure their health and longevity in your aquarium, it’s important to meet their specific care requirements. Here’s a detailed care guide for Amano shrimp:

 

Variations

The Snow White Amano Shrimp is a rare and selectively bred variation of the standard Amano shrimp (Caridina multidentata) characterized by its striking by its white color.

The Red Amano Shrimp is another selectively bred variation of the standard Amano shrimp (Caridina multidentata), known for its vibrant red coloration. 

The Lemon Yellow Amano Shrimp is another variation of the standard Amano shrimp (Caridina multidentata), distinguished by its vibrant yellowish-golden color.

 

Sex & Breeding

Amano shrimp (Caridina multidentata) exhibit sexual dimorphism, meaning there are physical differences between males and females. Here's how you can distinguish between the two:

Female Amano Shrimp

• Size: Female Amano shrimp are typically larger than males, reaching up to 2.5 inches (6.5 cm) in length.
• Body Shape: Females have a broader, rounder abdomen that is more noticeable, especially when they are carrying eggs or berried.
• Coloration: Females are often more transparent, but their body may appear slightly more opaque due to their egg sacs when they are gravid (carrying eggs).
• Eggs: When carrying eggs, females will have a visible cluster of eggs (usually green or brown) beneath their abdomen.

Male Amano Shrimp

• Size: Males are generally smaller, reaching around 1.5 to 2 inches (4 to 5 cm) in length.
• Body Shape: Males have a slimmer, more slender abdomen compared to females, especially when not carrying eggs.
• Coloration: Males are often slightly more transparent than females and do not have the same visible egg sacs.

Despite these differences, the distinction between males and females can be subtle, especially when they are not carrying eggs. In terms of behavior, males tend to be more active, especially during mating attempts.

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. However, if you're interested in giving breeding Amano shrimp a try, Avatar Aquatics has a great video on the matter:

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Size

Amano shrimp (Caridina multidentata) typically grow to a size of around 2 inches (5 cm) in length, although they can sometimes reach up to 2.5 inches (6.5 cm) under optimal conditions. This makes them one of the larger freshwater shrimp species commonly kept in aquariums. The size of the shrimp can vary slightly depending on factors such as water quality, diet, and overall tank conditions.

While they are not the largest shrimp species available for freshwater aquariums, their size is still impressive compared to smaller shrimp species like cherry shrimp or ghost shrimp. Their larger size and active foraging behavior make them excellent algae cleaners, as they are able to cover more area while scavenging for food.

 

Molting

Amano shrimp molt regularly as they grow, shedding their old exoskeleton to form a new one. This process typically occurs every few weeks or months, depending on the shrimp’s age and size. During molting, Amano shrimp are vulnerable and may hide to protect themselves from stress or predation. It is important to provide plenty of hiding spots in the aquarium to give them a sense of security.

If you notice a molt in the tank, it's usually harmless, and the exoskeleton should be left in the tank as it will decompose and provide nutrients to the tank. However, if your shrimp seem to be struggling during molting (e.g., not being able to shed their shell properly), it could be a sign of poor water quality or a calcium deficiency, and adjustments may be needed.

 

What's Their Diet?

Amano shrimp are omnivores, primarily feeding on algae, biofilm, and detritus in the tank. Their main role in an aquarium is to help control algae growth, but they also scavenge for any leftover food. 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. Occasionally, they enjoy protein-rich foods such as brine shrimp, daphnia, or high-protein shrimp pellets.

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. Keep in mind that overfeeding can lead to water issues, so it’s important to provide just enough food to avoid waste accumulation.

Amano shrimp (Caridina multidentata) are renowned for their exceptional ability to control algae in freshwater aquariums. They are particularly effective in reducing the growth of certain types of algae, making them a valuable addition to tanks with algae issues.

Types of Algae Amano Shrimp Eat

Amano shrimp are particularly skilled at consuming the following types of algae:

• Green Hair Algae: This is one of the most common algae types that Amano shrimp help control. They graze on the green, filamentous strands of hair algae, effectively reducing its spread in the tank.

• Brown Diatom Algae: Amano shrimp can also help clean up brown diatom algae, which often forms a dusty brown coating on aquarium surfaces. The shrimp feed on the algae film that develops on rocks, plants, and substrate.

• Green Spot Algae: While Amano shrimp are not as effective at eliminating green spot algae, they may still nibble on the spots found on glass or decorations, helping to reduce their growth.

• Soft Algae: They are adept at eating soft algae, which forms a slimy coating on surfaces such as leaves and decorations. This is particularly beneficial in planted tanks, where they help keep plants clear of algae buildup.

How Amano Shrimp Eat Algae

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. Their constant foraging behavior keeps the tank cleaner and prevents algae overgrowth from becoming a major issue.

Limitations

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. Additionally, Amano shrimp may not consume more stubborn types of algae, like black beard algae (BBA) or some forms of green spot algae.

Amano shrimp are most effective when the tank has a healthy balance of algae, and their grazing keeps it under control. They also benefit from a diet supplemented with other foods, such as algae wafers and blanched vegetables, to ensure they have enough to eat beyond just algae.

 

Behavior and Interaction

Amano shrimp are generally peaceful and social. They thrive in groups and are often seen scavenging for food throughout the tank. They are most active during dawn and dusk, foraging for algae and detritus. During the day, they may be less visible or retreat to more sheltered areas of the tank.

They are not territorial and will coexist well with other species as long as those species do not pose a threat. While they are generally peaceful, it's important to ensure that the tank environment remains stable and free from stressors.

By providing proper care and maintaining optimal water conditions, Amano shrimp can live a long and healthy life, contributing to the cleanliness and balance of your aquarium.

 

Tank Setup For Amano Shrimp

Amano shrimp do well in tanks as small as 10 gallons, but larger aquariums are preferable for stable water conditions and a larger environment to explore. 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. Avoid sharp-edged gravel as it may damage their delicate bodies.

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. 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. Sponge filters are often a good choice for shrimp tanks.

 

Water Maintenance

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. It's crucial to test the water regularly for ammonia, nitrites, nitrates, pH, and hardness to ensure that the water parameters stay within the recommended range.

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. Regular water testing is important to catch any changes in water chemistry that could harm the shrimp.

 

Tank Mates

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. Fish with large mouths, such as cichlids or bettas, can be a threat to Amano shrimp.

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. Therefore, it's best to keep them with species of similar size and temperament to ensure a harmonious environment.

 

Best Plants for Amano Shrimp Tanks

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. Some plants are particularly suitable for shrimp tanks:

1. Java Moss (Taxiphyllum barbieri): This plant provides a perfect environment for Amano shrimp to forage. It grows quickly and offers hiding spots for shrimp, especially during molting.
2. Anubias: A hardy, slow-growing plant with thick leaves that Amano shrimp will find appealing for grazing. Anubias is also relatively resistant to algae overgrowth.
3. Cryptocoryne: These plants have sturdy, broad leaves and can thrive in low to moderate light, making them suitable for shrimp tanks.
4. Java Fern (Microsorum pteropus): Java Fern is a resilient plant with tough leaves that Amano shrimp can graze on without damaging the plant itself.
5. Amazon Sword (Echinodorus amazonicus): A popular plant in many aquariums, Amazon Swords have broad leaves that can provide hiding spots for shrimp and are also grazed upon.
6. Marimo Moss Balls (Aegagropila linnaei): These spherical algae balls are not only a fun decoration but also a source of algae for the shrimp to feed on.

 

Common Health 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. Here are some of the common conditions and challenges Amano shrimp may face, along with the causes and ways to prevent or manage them:

1. Poor Water Quality

Amano shrimp are highly sensitive to water quality, and poor water conditions are one of the most common causes of stress, disease, or death. Inadequate water quality can lead to a variety of health problems, including respiratory distress and difficulty molting.

• 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. Test water parameters regularly.

• Chlorine/Chloramine: Tap water often contains chlorine or chloramine, which can be harmful to shrimp. Always treat tap water with a water conditioner to neutralize chlorine or chloramine before adding it to the aquarium.

• 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). Ensure stable water parameters and avoid drastic fluctuations.

2. Molting Issues

Molting, or shedding the exoskeleton, is a natural process for Amano shrimp as they grow. However, it can sometimes be a source of health issues, particularly if water quality or diet is inadequate.

• 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. To avoid this, ensure that the tank water has adequate calcium levels and offer a varied diet that includes calcium-rich foods like calcium supplements or crushed eggshells.

• 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. Make sure the tank has plenty of hiding spots, such as dense plant growth or decorations, to help the shrimp feel secure during this delicate process.

3. Stress and Aggression

Amano shrimp are peaceful creatures, but they can become stressed due to various factors. Stress can lead to health problems, including decreased immune function and molting issues.

• 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. It’s important to keep Amano shrimp with small, non-aggressive fish and other peaceful invertebrates.

• 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). Avoid placing the tank in locations with direct sunlight or near heaters or air conditioners, which can cause temperature swings.

• 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. It’s recommended to keep 3-6 shrimp per 10 gallons to avoid overcrowding.

4. Diseases and Infections

While Amano shrimp are generally hardy, they can still be susceptible to certain diseases, especially when stressed or exposed to poor water conditions.

• 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. If Ich occurs, it can be treated with copper-based medications, but be aware that some medications can be harmful to shrimp, so use with caution and remove shrimp from the treatment tank if possible.

• 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. If infection is suspected, isolate the affected shrimp and consider using antibacterial treatments designed for invertebrates.

• 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. To prevent fungal infections, ensure good water quality and avoid overfeeding, as uneaten food can lead to excess nutrients in the water, encouraging fungus growth.

5. Poor Diet and Nutritional Deficiencies

Amano shrimp are scavengers and rely on algae, detritus, and biofilm for food. However, a varied diet is essential to keep them healthy. A lack of proper nutrition can lead to problems like poor molting or weakened immune systems.

• Algae Dependence: While Amano shrimp are excellent algae eaters, they may not have enough algae in a newly established tank. To supplement their diet, provide algae wafers, shrimp pellets, or blanched vegetables such as zucchini, spinach, or cucumbers.

• https://www.superiorshrimpaquatics.com/blogs/news/understanding-and-managing-carbonate-hardness-kh-in-your-shrimp-aquariumDeficiency: Shrimp require adequate calcium for proper exoskeleton development. A calcium deficiency can lead to issues during molting. If your water is soft or your shrimp seem to have difficulty molting, you can add a calcium supplement or use mineral-rich substrates to provide them with the necessary nutrients.

6. Overfeeding and Water Pollution

Feeding Amano shrimp too much can lead to water pollution and deteriorating water quality, which, in turn, can cause stress and health problems. It’s important to avoid overfeeding, as uneaten food can break down and contribute to elevated ammonia, nitrites, and nitrates in the tank.

• Food Waste: Provide small amounts of food and remove uneaten portions after a few hours. Amano shrimp are effective at cleaning up leftover food, but it’s best to avoid feeding more than they can consume in a single sitting to prevent water quality issues.

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. Regular tank maintenance and monitoring of shrimp behavior are key to preventing and addressing any potential health problems.

 

General Care Tips

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. This will help them adjust to the new water conditions.

To avoid introducing diseases or parasites, it’s best to quarantine new shrimp for a week before adding them to your main tank. This will help prevent the spread of any potential issues to the rest of your aquarium inhabitants.

Lastly, avoid handling Amano shrimp directly. They are delicate creatures and can be injured easily. If you need to move them, use a net designed for shrimp or invertebrates.

 

Conclusion

In conclusion, Amano shrimp (Caridina multidentata) are highly beneficial and low-maintenance additions to freshwater aquariums. Their impressive ability to control algae, coupled with their peaceful nature and compatibility with a variety of tankmates, makes them an excellent choice for hobbyists looking to maintain clean and healthy aquariums. While they require stable water conditions, proper diet, and occasional attention to molting and water quality, Amano shrimp are generally hardy and thrive in well-maintained tanks. By providing them with the right environment, you can enjoy the many benefits they offer in controlling algae and contributing to a balanced aquatic ecosystem.