Amano Shrimp Care Guide

Amano shrimp are the best algae-eaters in the hobby — the only common animal that will clear hair and thread algae and even pick at black beard algae, which cherry shrimp won't touch. But two facts decide whether they earn their keep: a clean tank starves them, so you must feed them, and they cannot breed in freshwater, so you buy them as a standing crew to replace, not a colony.

Amano Shrimp at a glance

The sourced figures the welfare engine uses to judge Amano Shrimp — the parseable key facts.

Where it comes from

Amano shrimp are Caridina multidentata (Stimpson, 1860), an atyid shrimp native to Japan and Taiwan. They come from fast-flowing, clear, well-oxygenated freshwater streams full of rocks, leaf litter and the algae and biofilm they graze. The defining wild trait is amphidromy: the adults live and spawn in freshwater, but the newly hatched larvae are swept downstream to brackish or salt water to develop, and the juveniles then migrate back upstream into freshwater. That single biological detail is why they will not breed in your tank — the larvae physically need the sea. The cool, flowing, moderately mineralised origin also explains two things about their care: they tolerate cooler water unusually well, and they need real general hardness in the water to harden a new shell after each moult. They value cover — plants, wood and leaf litter — both as grazing surface and as a refuge when they moult.

Did you know?

• The best algae-eating shrimp, and one of the only animals that eats black beard algae. They demolish hair, thread and brush algae and, for a hungry group, will take BBA — which cherry shrimp ignore entirely.
• Named after a person. Takashi Amano, the legendary Japanese aquascaper, made them the standard cleanup crew of the planted nature-aquarium movement in the 1980s–90s.
• They time-travelled their own name. Known as Caridina japonica (De Man, 1892) for decades, they were renamed Caridina multidentata in 2006 because Stimpson had already described the same shrimp in 1860 — under the rule of priority, the older name wins.
• They can't breed in your tank, by design of their biology. Like nerite snails their larvae need the sea: eggs hatch in freshwater, larvae drift to salt water, juveniles march back upstream. Almost every Amano sold is wild-caught.
• A single female can carry around 1,800 eggs — yet in a freshwater tank essentially none survive, because the larvae need brackish water. High fecundity, near-zero home recruitment.
• Escape artists. They climb cords and airline tubing out of open tanks, so a tight lid is part of the care sheet. And as stream natives they're cool-water tolerant, comfortable down to ~18 °C and keepable unheated in many temperate rooms.

Tank size — and why

A 5-gallon nano is the practical floor, with 10 gallons or more preferred for stability and for giving an algae crew enough surface to work. Their bioload is low — they are grazers, not waste machines — so the constraint is parameter stability (as with all shrimp) plus simply having enough algae to go round. A rough stocking guide is about one Amano per 2 gallons, so they aren't all competing for the same patch. On size, sources genuinely disagree: Wikipedia gives a conservative 2.5–3.5 cm (wild-measured), while hobby care sources report ~4–5 cm, with females reaching 5–6 cm and males 3–4 cm. A realistic typical adult is about 3.5–4.5 cm, females clearly larger. Our stored 5 cm sits at the very top of that range — defensible as a large female or a maximum, but it overstates a typical adult.

As a guide, a 20-gallon tank comfortably suits about 8–11 Amano Shrimp as a single-species display, leaving room for tankmates.

Water parameters in practice

General hardness is the welfare-critical lever, and the engine doesn't store a hardness field, so this is the number to get right: aim for GH about 6–8 °dGH (tolerated roughly 5–15), with a stable KH around 2–4 °dKH and TDS about 150–200 ppm. Dissolved calcium and magnesium are what the shrimp uses to harden its new shell after each moult — too-soft water (below roughly 4–5 °dGH) leaves the shell unable to set and the moult fails, which is fatal. Temperature is forgiving and runs cool: ideal is about 22–24 °C, but they're survivable across roughly 18–28 °C and genuinely comfortable at the 18 °C low end thanks to their stream origin, so they can be kept unheated in many temperate rooms — the high end (28 °C-plus) is the stressful side. pH is best at 6.5–7.5 and tolerated 6.0–8.0. Stability beats precision: a sudden GH/KH/TDS swing, usually from a big water change with much softer water, is a leading moult-failure trigger, so keep changes small and parameter-matched, and re-mineralise RO water with a shrimp mineral if your tap is too soft or carries copper.

Diet & feeding

This is the reason to buy them. Amano are widely regarded as the single best algae-eating shrimp — bigger appetite and tougher palate than cherry shrimp. Their specialty is hair, thread and string algae, which they actively tear apart, and they are one of the very few animals that will even eat black beard algae (BBA), though be honest about that one: results on BBA are mixed and conditional — it usually takes a hungry group and they prefer it softened (for example after a spot-treatment), and a well-fed Amano may ignore it. They are weak on flat film and spot algae on glass — for that, nerite snails or otocinclus are better. The critical expectation to set: a clean tank is not enough food. Once they've eaten the visible algae you must feed them at least a few times a week — sinking shrimp or algae foods, leftover fish food, blanched or rotting leaves and vegetables, ideally calcium-rich to support moulting — or they starve, and a hungry Amano gets boisterous. They also eat their own shed exoskeleton for its minerals, so leave moults in the tank. Don't overfeed, though: feed the fish heavily and the shrimp will ignore the very algae you bought them for, and the excess fouls the water.

Gear & setup

A tight-fitting lid is mandatory — Amano are expert escapers, notorious for climbing cords and airline tubing out of an open tank to die on the floor, so seal the gaps where cables and tubing exit. Beyond that: add them only to a cycled, established tank so there's biofilm to graze and no ammonia spike; give them dense live plants, moss, wood and leaf litter for grazing surface and, critically, a refuge when they moult and are soft and defenceless; and provide moderate flow and good oxygenation to suit their fast-stream origin, with a shrimp-safe intake (a sponge filter or guarded intake) so they aren't sucked in.

Temperament & behaviour

Peaceful, with no meaningful intraspecific aggression and no ability to nip fins — a calm, useful tank citizen day to day. They don't need to be kept in a group, but they do better in one: several together (commonly 3–6 or more) are bolder and more visible, while a lone shrimp tends to hide. Because they won't breed in freshwater, you stock them as a standing algae crew sized to the tank, not as a self-renewing colony — when they die of old age, you replace them. The one behaviour to know is at feeding time, when they turn into extremely aggressive eaters and will shove smaller dwarf shrimp off the food. And when underfed they get frantic and fearless: a hungry Amano may pester slow or sick fish and even nibble the slime coat of a slow-moving fish like a betta. They are almost never the actual cause of a death — overwhelmingly they're scavengers cleaning up animals that were already dying — but the behaviour is real and looks alarming, and the fix is simply to keep them fed.

Group & social needs

No strict group requirement, unlike a breeding cherry colony — three is acceptable, and several sources suggest six or more reduces stress and makes them bolder. The better guide is to stock to the algae load at roughly one shrimp per 2 gallons rather than to a fixed minimum. They're safe to house with cherry and other dwarf shrimp (they cannot interbreed with Neocaridina), but they'll out-compete smaller shrimp at feeding, so put out enough food for everyone.

Compatible tank mates (preview)

A short, engine-cleared shortlist — the species TankStocking's welfare engine clears with Amano Shrimp and that suit its size and temperament best. Tap any to load the pairing in the planner.

• Bamboo Shrimp (Wood/Fan Shrimp) — Peaceful temperament, similar adult size.
• Black Neon Tetra — Peaceful temperament, similar adult size.
• Black Phantom Tetra — Peaceful temperament, similar adult size.

This engine-cleared shortlist is Amano Shrimp's tankmate surface for now — a dedicated tank-mates guide can follow for high-demand species.

Breeding & sexing

The load-bearing fact: they will not breed in a freshwater tank. Females berry readily — a female carries a large clutch under her swimmerets for about four to five weeks, and fecundity is high (averaging roughly 1,800 eggs, with reports from ~750 to ~4,400) — but the hatchlings are tiny planktonic zoea larvae that require brackish or salt water to survive, and in freshwater they die within days. Real captive breeding is an advanced, rarely-successful project: you must move newly hatched larvae to brackish water (ideally ~32 ppt, around 1.024 specific gravity) within about a day, feed them live microalgae such as cultured Tetraselmis through roughly nine zoea stages over 40–45 days, then move the juveniles back to freshwater. Because almost nobody pulls this off at home, almost all Amano shrimp sold are wild-caught — so treat them as livestock to replace, not a colony. Sexing is clear once mature: females are larger and deeper-bodied with a row of dashes (a broken line) along the lower flank and often a green or amber "saddle" of developing eggs on the back; males are smaller and slimmer with a row of evenly spaced round dots. This is the exact mirror image of the cherry shrimp, which hatches directly into miniature adults and breeds effortlessly in freshwater.

Lifespan

About 2–3 years is the usual planning figure, with some care sources giving 2–5; they are larger and longer-lived than the ~1–2 year cherry shrimp, so a single Amano is a multi-year animal rather than a fast-turnover colony member. Anecdotal reports of 6–10-plus years exist but are uncorroborated outliers. The big early killer is transport and acclimation shock — Amano often die in the first couple of weeks from the stress of shipping or a sudden shift in parameters; survive that window and they're hardy. After that: unstable GH/KH/TDS (failed moults), copper exposure, sustained high temperature, ammonia or nitrite from an uncycled tank, and predation (especially mid-moult).

Common mistakes

• Expecting them to breed in your freshwater tank. They won't — the larvae need brackish or salt water. If you want a self-sustaining shrimp population, buy cherry/Neocaridina; buy Amano for algae control and plan to replace them every few years.
• Buying them as a one-shot algae fix and then not feeding them. Once the visible algae is gone they need feeding a few times a week or they starve — and if you feed the fish heavily, they'll ignore the algae you wanted cleaned.
• Ignoring GH or using water that's too soft. The number-one invert mistake, causing failed moults and death. Aim for GH about 6–8 °dGH and re-mineralise soft RO water before adding shrimp.
• No lid, or unsealed cord and tubing gaps. Amano are expert escapers and will climb out. A tight, gap-sealed lid is non-negotiable.
• Adding them to a tank with shrimp-eating fish. Bigger than cherries, but cichlids, bettas, goldfish, large gouramis, large barbs, loaches and puffers still eat them, especially mid-moult.
• Dosing copper medications, algaecides or some ferts with shrimp present. Lethal to all inverts — read every label.
• Dumping them in without slow acclimation. Transport and parameter shock kills many in the first two weeks — drip-acclimate.
• Underfeeding them and then blaming them for "attacking" fish. A hungry Amano pesters slow or sick fish; keep them fed.

Signs of trouble

• A white ring around the body (the "White Ring of Death") — a failed moult where the shell splits all the way round instead of at the neck; fatal and not reversible, usually a hardness or parameter-swing problem.
• Mass death within the first couple of weeks after introduction — the signature of transport/acclimation shock or copper in the water.
• Sudden death shortly after a water change — a parameter-swing signature; keep changes small and matched.
• Frantic, fearless behaviour and pestering slow or sick fish — usually hunger; feed them.
• Fluffy white tufts (Vorticella) or small white appendages on the head (Scutariella) — treat with a salt dip, never copper.

Is this fish right for you?

Don't buy Amano shrimp if you want a self-sustaining shrimp colony — they cannot breed in freshwater, so they're a crew you replace, not a population that renews itself; buy cherry shrimp for that. Don't buy them if your water is very soft and you won't re-mineralise it, because too-soft water causes fatal failed moults. Don't add them to a tank with shrimp-eating fish (cichlids, bettas, goldfish, large gouramis, barbs, loaches, puffers), and remember most medications contain copper, which is lethal, so a sick Amano tank is hard to treat. There's no dyed or deformed-morph ethical issue here — Amano have no colour strains — but because most are wild-caught, expect high early mortality from stressed shipments, so buy from a vendor with healthy, well-acclimated stock and quarantine new arrivals.

Bringing one home

Drip-acclimate slowly — transport and a sudden shift in parameters is the most common early death for this species, and shrimp are sensitive to fast swings in hardness and TDS. Add them only to a mature, cycled tank with established biofilm, quarantine new stock (Scutariella and Vorticella can hitch-hike), and never use copper-based treatments on the tank.

Common questions

Do Amano shrimp really eat algae, including black beard algae?

Yes — they're the best algae-eating shrimp, specialists at hair and thread algae, and one of the few animals that will even eat black beard algae (which cherry shrimp won't touch). The BBA result is conditional, though: it takes a hungry group and they prefer it softened. They're weak on flat film/spot algae on glass.

Can Amano shrimp breed in a freshwater tank?

No. Females readily carry eggs, but the larvae are planktonic and need brackish or salt water (about 32 ppt) to survive — in freshwater they die within days. Home breeding is an advanced, rarely-successful project, which is why almost all Amano shrimp sold are wild-caught. Buy cherry shrimp if you want a breeding colony.

Are Amano shrimp safe with fish?

Safer than cherry shrimp because they're bigger (about 3.5–4.5 cm), so small community fish can't eat them — but they're not invulnerable. Avoid cichlids, bettas, goldfish, large gouramis, large barbs, loaches and puffers, which can eat them, especially just after a moult. Hungry Amano can also pester slow or sick fish, so keep them fed.

How big do Amano shrimp get?

Typically about 3.5–4.5 cm, with females reaching 5–6 cm and males 3–4 cm. Sources disagree — Wikipedia gives a conservative 2.5–3.5 cm for wild animals, hobby sources up to ~5 cm for well-fed captive females.

Why did my Amano shrimp die after a water change (or turn white)?

Almost always a failed moult from a parameter swing or too-soft water. They need general hardness — aim for GH about 6–8 °dGH — to harden a new shell, and a big water change with much softer water can trigger a fatal moult. Keep changes small and parameter-matched.

Do Amano shrimp need a lid?

Yes — they're expert escapers that climb cords and airline tubing out of open tanks. Use a tight-fitting lid and seal the gaps where cables and tubing exit.

Sources & confidence

Sources & confidence (9 species)

These back the Amano Shrimp figures and the previewed tank mates above. Each figure is read from the TankStocking species database (v2026.06); below is the care reference behind it and how confident we are in that data. Confidence reflects the source quality, not whether any pairing is safe. Full source list and the welfare model are on the methodology page.

• Amano Shrimp Caridina multidentata — Aquarium Co-Op amano shrimp care; Aquadiction high confidence
• Bamboo Shrimp (Wood/Fan Shrimp) Atyopsis moluccensis — Aquariadise (aquariadise.com/caresheet-bamboo-shrimp-atyopsis-moluccensis) high confidence
• Black Neon Tetra Hyphessobrycon herbertaxelrodi — Seriously Fish / Aqua-Fish (Hyphessobrycon herbertaxelrodi) high confidence
• Black Phantom Tetra Hyphessobrycon megalopterus — Seriously Fish (Hyphessobrycon megalopterus) high confidence
• Bleeding Heart Tetra Hyphessobrycon erythrostigma — Seriously Fish (Hyphessobrycon erythrostigma) high confidence
• Boesemani Rainbowfish Melanotaenia boesemani — Seriously Fish; Aquarium Co-Op Boesemani guide high confidence
• Bolivian Ram Mikrogeophagus altispinosus — Seriously Fish (seriouslyfish.com/species/mikrogeophagus-altispinosus) high confidence
• Brilliant Rasbora Rasbora einthovenii — Seriously Fish (seriouslyfish.com/species/rasbora-einthovenii) high confidence
• Bronze Corydoras Corydoras aeneus — Seriously Fish (seriouslyfish.com/species/corydoras-aeneus) high confidence

Care-guide sources (8)

This guide synthesises the references below; where they disagree, the range and the disagreement are noted in the text above. The figures in the key-facts box are read from the TankStocking species database (v2026.06). Full welfare model on the methodology page.

• Wikipedia — Caridina multidentata — authority (Stimpson, 1860), family Atyidae, C. japonica synonym + 2006 rename, common names, native range (Japan/Taiwan), size 25–35 mm, fast-flowing habitat, amphidromous life cycle (freshwater spawning → saltwater larvae → freshwater adults), temp 18–28 °C, pH ~6.5–7.5, algae diet
• Aquarium Co-Op — Care Guide for Amano Shrimp — temp 65–82 °F (18–28 °C), pH 6–8, "moderate to hard GH," size 1.5–2 in (4–5 cm), >=5 gal (10+ ideal), tight lid / escape risk, "do not need to be kept in groups," eats hair/thread/black-beard algae but weak on flat film algae, "can't survive off algae alone… provide additional food," larvae need brackish/salt water so won't breed in freshwater, sexing dots (M) vs dashes (F), tankmate good/bad list, eat their own moults
• aquariumbreeder — Breeding and Life Cycle of Amano Shrimp — larvae need brackish water, ideal 32 ppt (1.024 SG), tolerated 17–34 ppt; eggs carried 4–5 weeks (~25 d at 25.5 °C); 9 zoea stages, ~40–45 d; larvae filter-feed cultured Tetraselmis; amphidromous migration; almost all Amano are wild-caught; fecundity avg ~1,872 eggs (range 747–4,391)
• aquariumbreeder — Amano Shrimp: Detailed Guide (Care, Diet and Breeding) — size 3–6 cm (females 5–6, males 3–4), lifespan 2–5 yr, temp 18–28 °C (ideal 24), pH 7.0–7.4 (6.5–8.0), GH 7–8 (5–15), KH 2–4 (1–8), TDS 150–200, min 10 gal, ~1 shrimp/2 gal (keep 6–10), eats hair/brush/string + black-beard algae, weak on spot algae, "extremely aggressive eaters," out-compete smaller shrimp, copper kills all inverts, sexing dots vs dashes
• Shrimp Science — General Hardness (GH) for Shrimp Tanks — GH supplies calcium/magnesium for moulting; too-low GH (<~4–5) causes failed moults; ideal moulting band; stability over swings; White Ring of Death physics
• AquariumStoreDepot — Best Amano Shrimp Tank Mates — Amano larger than cherry but still prey; avoid cichlids/angelfish/bettas/large gouramis/puffers/large barbs/goldfish; safe small community fish; most vulnerable mid-moult
• ouraquariumlife / UKAPS / PlantedTank forums — Do Amano shrimp attack fish? — Amano are scavengers attuned to dying animals; ~99.9% not the cause of death; hungry shrimp may nibble the slime coat of slow fish (e.g. betta); keep them fed
• Shrimpy Business / Aquarium Care Basics — Amano lifespan & care — lifespan 2–3 years (some 3–5), transport/acclimation shock as the big early killer, drip-acclimate, general care corroboration

More on Amano Shrimp

Related guides on TankStocking — each scored by the same welfare engine as the planner.

This care guide is a sourced planning reference, not veterinary advice — individual fish, filtration and maintenance all matter. Cycle the tank, test your water, and observe your fish. How TankStocking works →