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Amano shrimp (Caridina multidentata) are among the most popular inhabitants of planted aquariums. Their appetite for algae, busy behaviour and ability to live with many peaceful fish make them appealing companions. There is more to them than algae removal, however. Given suitable water, regular food and places to shelter, they can live for years and provide something interesting to watch every day.
This guide covers their natural habitat, aquarium requirements, diet, tank mates and the reasons breeding them differs from breeding other familiar freshwater shrimp.
What Is an Amano Shrimp?
Caridina multidentata is a freshwater shrimp in the family Atyidae. Its scientific name is written Caridina multidentata Stimpson, 1860. The older name Caridina japonica De Man, 1892 refers to the same species; the synonymy was clarified in a 2006 taxonomic study. Amanos are not a transparent colour form or another trade name for Neocaridina davidi.
Natural distribution and habitat
Japan and Taiwan are central to the species' recorded range, including Japan's Ogasawara and Ryukyu islands. Cai and colleagues' 2006 treatment also lists Fiji and Madagascar. Rather than presenting those distant records as a definitive, complete modern range map, it is more useful for husbandry to understand the shrimp's riverine habitat.
Amanos graze rocky surfaces in flowing streams and rivers. Their life cycle connects freshwater with the sea: adults live in freshwater, while larvae develop in saline environments. In an aquarium, the practical lesson is to provide clean, well-oxygenated water and grazing surfaces, not to add salt to the adult tank.
Adult size, appearance and lifespan
Adults commonly measure about 4–5 cm, with large females approaching 5–6 cm. Their translucent, sometimes grey-brown bodies carry dark spots and short dashes along the flanks. Females are generally larger and fuller through the abdomen.
A practical care plan can allow for a lifespan of roughly 3–5 years. This is a husbandry expectation reported by specialist keepers, not a fixed experimentally established average. Individuals living five or six years and longer are also reported. An adult's age at purchase is often unknown, so time spent in your aquarium does not necessarily equal its total lifespan.
What Size Aquarium Do Amano Shrimp Need?
A mature planted aquarium of around 50–60 litres and 60 cm length, starting with five or six shrimp, is a practical example. It is consistent with Aquasabi's 54-litre/60-cm recommendation and sources supporting small-group care. Choose more room for a larger group or a heavily stocked community. Some specialists, including Garnelenhaus, favour tanks of 80 cm or longer; 60 cm should not be treated as an absolute biological minimum for every setup.
A single Amano can live alone and does not have an obligatory schooling requirement. Nevertheless, several individuals offer a better starting point for observing their foraging behaviour. Do not increase numbers according to litres alone: floor and grazing area, food access, filtration and other inhabitants all matter.
Arrange wood, rocks, plants and retreats
Position stable rocks and wood so shrimp can move around them. Moss, attached plants and dense planted corners add grazing surfaces. Leave an open area at the front for observation and feeding. At the same volume, adequate floor area is generally more useful than a very tall, narrow layout.
After moulting, a shrimp is temporarily vulnerable. Root tangles and planted spaces that fish cannot enter become especially valuable then. Avoid repeatedly lifting decorations simply to make a hiding shrimp visible.
Lids and safe filtration
Use a cover or appropriate escape protection and inspect openings around cables and tubing. Amanos can leave an aquarium. Distinguish one new arrival exploring from the entire group climbing towards the surface; a sudden group-wide escape attempt calls for an immediate check of oxygenation and water quality.
Protect the filter intake with a suitable sponge and remove exposed impeller or trapping hazards. Mature biological filtration controls ammonia and nitrite; clear water alone does not show that a new filter is ready. Maintain surface gas exchange without turning the whole aquarium into one forceful jet. The sponge filter guide explains a useful option.
What Water Parameters Do Amano Shrimp Need?
20–26 °C, pH 6.5–8.0, GH 5–15 dGH and KH 3–10 dKH are practical starting ranges for adult care in a home aquarium. Aim for stable conditions compatible with the other inhabitants instead of continually chasing one ideal number.
Parameter
Practical care target
Application
Temperature
20–26 °C
Stable, well-oxygenated water rather than continuous high heat.
pH
6.5–8.0
Avoid rapid corrections with acids or buffers.
GH
5–15 dGH
Provide an appropriate calcium and magnesium balance.
KH
3–10 dKH
A starting target for a conventional setup without active substrate.
Ammonia/ammonium
0 mg/L; undetectable on the test
Interpret results alongside pH and temperature.
Nitrite
0 mg/L; undetectable on the test
Investigate any positive result.
Nitrate
Preferably below 20 mg/L as NO₃
A precautionary maintenance target, not a species-specific toxicity threshold.
Salinity for adult care
Freshwater; no routine marine salt addition
Prepare larval rearing water separately.
The temperature range follows Aquarium-Guide's 20–26 °C care recommendation; pH and GH match The Shrimp Farm's species-care ranges. KH 3–10 dKH is a starting selection within that source's 1–10 dKH and Garnelenhaus's 3–20 dKH ranges. Do not rapidly alter a successful low-KH aquarium simply to fit this table. The nitrate target below 20 mg/L is a cautious selection from general aquarium maintenance recommendations.
Adults are maintained in freshwater. The larvae's brackish-to-marine development does not mean adults need saline water. Table salt is not a substitute for appropriate mineral preparation either.
RO water and water changes
RO is optional when your tap water is suitable. If you use it, prepare and remineralise water in a separate container, checking GH, KH and temperature before adding it. Do not pour mineral powder over the animals. TDS or conductivity does not replace GH and KH testing.
Begin with regular small-to-moderate weekly water changes and adjust the amount to feeding load and test results. Treat chlorine/chloramine and reduce temperature and hardness differences. Replacing evaporated water is a different task from replacing water removed during maintenance. Read the pH, KH and GH and water change guides for the practical details.
What Do Amano Shrimp Eat?
Amano shrimp are grazing omnivores. Alongside algae and biofilm, they eat suitable prepared foods. Good husbandry does not mean starving them into cleaning the aquarium.
Which algae do they eat?
Filamentous algae: They can help with accessible fine, soft hair or thread algae. Manually reducing long, dense masses first makes the remaining surfaces easier to reach.
Soft green algae: They may graze newly developing films and some soft growth. Not every visible green alga is an equivalent food source.
Black beard algae: Keepers report consumption of some tufts, but established tough growth should not be expected to disappear reliably.
Hard green spot algae: Amanos are a poor choice for firmly attached spots on glass or leaves. Use an appropriate glass scraper and address the reason the algae are developing.
Consumption varies with algal texture and identity, access to the surface and the availability of other food. A shrimp grazing less algae while prepared food is available is not failing to do its job.
What if there is no visible algae?
Biofilm on mature surfaces, small organic particles collected on plants and prepared shrimp foods provide alternatives. A balanced shrimp food with a clear formulation can be the dietary base. Small amounts of suitable vegetables or properly prepared leaves from a reliable source can supplement it; do not assume that vegetables alone or one algae wafer supply every nutrient.
Offer additions such as blanched courgette in small portions and remove leftovers. Food that softens, breaks apart or smells unpleasant should not remain in the aquarium. A pile of decaying feed is not necessary to establish biofilm.
How often should they be fed?
In an aquarium with little natural food, start with a small daily offering. In a mature tank with extensive grazing and access to some fish food, an extra meal every day may be unnecessary. Actual consumption should guide the decision more than the calendar.
Place food where you can see it. Check during the first 15–30 minutes whether the animals reach it, then observe how much remains over the next one or two hours. These times are an example observation routine, not a universal instruction to leave every food in the tank for that long. Follow the product's guidance, reduce portions that remain and remove perishable leftovers. If Neocaridina cannot reach the food, change its distribution before simply adding more.
Will they steal other animals' food?
Yes. An Amano may carry away a substantial piece and outpace small shrimp or slow-feeding fish. Distribute small portions among several locations. Check that food intended for bottom-dwelling fish actually reaches those fish.
Will they remove every alga?
No. They can assist with some algae, but cannot independently solve problems caused by lighting, plant growth, nutrient balance and maintenance. Before adding more shrimp, assess the underlying cause and the food available to existing animals.
Which Fish Can Live with Amano Shrimp?
Small-to-medium fish with mouths and feeding behaviour unlikely to threaten the shrimp, and compatible water requirements, are better candidates. A peaceful label alone is insufficient: adult size, hunting behaviour and access to newly moulted shrimp matter.
Tetras: Small, calm schooling species may suit adult Amanos. Larger, assertive tetras are a different proposition, and small shrimp remain more vulnerable.
Rasboras: Small-mouthed, peaceful species are useful candidates. Check the overlap in conditions for species requiring particularly soft, acidic or warm water.
Corydoras: Species sharing suitable temperatures can generally be considered with adult Amanos. Competition on the floor is possible, so confirm both receive food.
Otocinclus: Often suitable companions, but they also need mature grazing surfaces and sufficient food. Do not introduce two types of algae grazer into a food-poor new aquarium.
Other freshwater invertebrates: Nerites and some small snails may be appropriate when their water requirements fit. Being an invertebrate does not guarantee compatibility; predatory crayfish and crabs are excluded from this recommendation.
Angelfish: This is not a risk-free combination. Adult Amanos have a size advantage, but small, newly introduced or recently moulted shrimp may be captured. Retreats can reduce risk without removing it. Use a separate aquarium when shrimp safety is the priority.
Large or predatory cichlids: Avoid animals likely to treat shrimp as food. A fish appearing calm outside feeding time does not establish safe compatibility.
The angelfish care guide covers the fish's own space and companion requirements.
Can Amanos live with Neocaridina?
Yes, when their water requirements overlap. Amanos are larger and can dominate feeding. Provide mossy retreats and separate food locations. Do not assume Neocaridina juveniles or newly moulted individuals are absolutely safe: opportunistic predation has also been observed. A separate colony is easier to manage when maximising juvenile survival is the aim.
Caridina multidentata and Neocaridina davidi do not interbreed to produce shared colour lines. Keeping them together does not mix their colours. Compare the needs of both using the Neocaridina care guide.
How to Tell Male and Female Amano Shrimp Apart
Females are generally larger, with a rounder abdomen and broader lower side plates that accommodate eggs. Males look slimmer. Along the flanks, males usually have separated dots, while females, particularly in the lower row, tend to show elongated spots or short dashes.
A yellowish-green saddle behind the head may show developing ovaries; this is not in the same position as eggs carried beneath the abdomen. A berried female holds and fans many small eggs on her swimming legs. Assess size, abdomen and markings together. One feature alone may be inconclusive in a young animal or a photograph taken from an awkward angle.
How Do Amano Shrimp Breed?
Following mating, the female carries eggs on the swimming legs beneath her abdomen. Eggs can develop and hatch in freshwater. The hatchlings are free-swimming larvae rather than miniature adults. Completing their development requires separate salinity and feeding conditions.
Neocaridina, by contrast, hatch looking like tiny shrimp and can grow in a suitable freshwater aquarium. A berried Amano therefore does not predict a growing juvenile colony in the adult tank. Home breeding is possible, but needs a separate larval system and food prepared beforehand. Do not salt the adult aquarium.
Hiding for a while after moulting, or behaving cautiously during the first days in a new aquarium, can be normal. One individual resting briefly and the entire group suddenly becoming inactive require different interpretations.
First check temperature and oxygenation. Is the filter running and the surface moving? In a CO₂ aquarium, assess the schedule and possible excess gas input; increase aeration when necessary.
Measure ammonia/ammonium and nitrite. A positive result calls for investigation of overfeeding, a dead animal, filter failure or an immature setup. Record nitrate and pH as well.
Review recent changes. If the problem followed maintenance, check replacement-water temperature, GH/KH and chlorine/chloramine treatment. Adding water slowly does not by itself make a large mineral mismatch safe.
Consider contamination. Have plants, medication, a copper treatment, cleaning agents, sprays or metal objects recently been introduced? Avoid products without confirmed shrimp compatibility. Do not equate a trace-element fertiliser used as directed with copper at treatment concentrations: formulation and dose matter.
Observe the fish. A shrimp that is continually chased or cannot approach food may be in an unsuitable community even when tests look satisfactory.
For a measured problem, stop its source and carry out the necessary maintenance with well-oxygenated, appropriately prepared replacement water. Do not respond to a symptom with random medication or minerals. A clear empty cast is not a dead shrimp; a carcass containing tissue should not be left to deteriorate.
Are Amano Shrimp Suitable for Beginners?
Yes. A mature aquarium, suitable water and safe companions make them a reasonable beginner choice. They should not be added on day one to clean a newly assembled tank. Keep care and breeding goals separate: Amanos can suit a first shrimp-keeping project, while Neocaridina may better suit someone seeking a colony that readily produces growing juveniles.
Frequently Asked Questions
How long do Amano shrimp live?
A practical expectation is around 3–5 years. Longer lives are reported, but age at purchase and previous care affect the outcome.
How big do they grow?
Commonly 4–5 cm, with large females around 5–6 cm. Males are usually smaller.
Can an Amano live alone?
Yes. In a suitable aquarium, a starting group of five or six is preferable for observing their behaviour.
Can they live without a heater?
Yes, if actual water temperature remains suitable and stable throughout the year. Check the aquarium thermometer by day and night rather than relying on room temperature. A cooling room may require a controlled heater.
Do they eat black beard algae?
They may consume some tufts, but should not be relied on to remove established growth. Do not starve the animals to force the issue.
Can they live with fish?
Yes, with small-mouthed, non-predatory species sharing compatible conditions. Angelfish and large cichlids present substantially greater risk.
Do they reproduce in freshwater?
Mating, egg development and hatching can occur in freshwater. Successfully raising the larvae in an ordinary freshwater aquarium is not expected; they need a separate saline larval phase.
Why do they try to leave the aquarium?
Exploration and acclimation may contribute. Sudden or group-wide attempts call for checks of oxygen, ammonia/nitrite, temperature, CO₂ and recent contaminants. Closing escape gaps does not replace investigating the cause.
OATA: Freshwater shrimp and snails — general invertebrate care and ammonia/nitrite targets; outdated species labels are corrected here using current taxonomy.
