Amano Shrimp: Complete Care Guide

Why Amano shrimp belong in almost every community tank

Caridina multidentata is the best algae-grazing invertebrate available to freshwater hobbyists - full stop. A group of ten working through a planted tank overnight will clear filamentous algae that would take you an hour to remove by hand. They're large enough (up to 5 cm / 2 inches) that most community fish ignore them, hardy enough for beginners, and entertaining enough that experienced aquarists keep them in display tanks alongside high-end Caridina breeding setups.

They're not a novelty. They're a functional part of a balanced planted aquarium, and once you've kept a healthy group you'll struggle to imagine a tank without them.

Tank setup and water parameters

Amanos originate from freshwater streams and rivers across Japan and the Korean peninsula - habitats with relatively stable, well-oxygenated water and plenty of surfaces covered in biofilm and algae. Replicating that isn't complicated, but a few things matter more than others.

Water chemistry

Keep temperature between 20-27°C (68-81°F). They tolerate the cooler end better than most shrimp - 22-24°C (72-75°F) is the sweet spot for activity and longevity. pH should sit between 6.5 and 7.5. Unlike Caridina breeding species such as Crystal Reds, Amanos aren't fussy about exact hardness, and they'll thrive in the moderately hard tap water that most UK and US fishkeepers have (GH 6-12 dGH is fine).

What they cannot tolerate is ammonia or nitrite at any level, and nitrate above 20-30 ppm starts to stress them visibly. A fully cycled tank isn't optional - see how to cycle a fish tank if you're setting up fresh. Amanos added to an uncycled or unstable tank will die within days, and new keepers often blame the shrimp rather than the water.

Tank size and filtration

The 40 L (11 US gal) minimum is realistic for a small group of five or six shrimp kept without other livestock. If you're adding Amanos to a community tank - which is the most common scenario - the tank size is dictated by your fish stock, not the shrimp. Check your stocking with the free stocking calculator before adding anything.

Filtration should be gentle but effective. Sponge filters or spray bars that disperse flow work well. Strong intakes on external filters will trap shrimp - cover them with a pre-filter sponge. Amanos are surprisingly powerful swimmers but juveniles and moulting adults are vulnerable.

Plants and hardscape

Heavily planted tanks suit Amanos extremely well. They graze constantly - on algae, on decomposing plant matter, on the biofilm that colonises driftwood and stones. Java moss, Anubias, and fine-leaved stem plants give them grazing surfaces and cover. A tank with no plants or hardscape is a poor environment for them; they'll spend all their time exposed and stressed.

Feeding

In an established planted tank with some algae growth, Amanos largely feed themselves. They graze continuously through the day and night, picking at surfaces with their small front claws. You don't need to feed them heavily - overfeeding the tank is one of the main causes of the algae problems people buy Amanos to fix in the first place.

That said, if your tank is very clean - bright lights, CO2, fast-growing plants outcompeting algae - supplement with blanched vegetables (zucchini, spinach, cucumber) two or three times a week, or a quality shrimp-specific pellet. Sinking wafers designed for bottom feeders also work. Remove uneaten food after a few hours to avoid ammonia spikes.

In a community tank with regular fish feeding, leftover food reaching the substrate usually provides enough supplemental nutrition. Amanos are not shy about stealing a sinking pellet from a corydoras.

What Amano shrimp actually eat - and what they won't touch

Hair algae (including Cladophora and thread algae) is where Amanos genuinely earn their reputation. They'll work through a tank infested with it methodically and efficiently. They're also effective on green dust algae on glass, biofilm on hardscape, and diatoms during tank maturation.

They will not reliably eat black beard algae (BBA), blue-green algae (which is actually cyanobacteria), or spot algae on glass. Some individual shrimp will nibble BBA when hungry, but don't count on it. They also won't solve a tank that's chronically overloaded with phosphate or nitrate - algae there will regrow faster than any shrimp crew can handle. Address water parameters first; the shrimp are the finishing crew, not the solution.

Compatible tank mates

Amanos are peaceful and relatively large for shrimp, which makes them compatible with a wider range of community fish than smaller Neocaridina species. Even so, they're not invincible.

Safe tank mates include: small tetras (Hyphessobrycon spp.), rasboras, corydoras, otocinclus, small plecos, gouramis under 8 cm, and other peaceful bottom dwellers. Avoid anything with a mouth large enough to fit an adult Amano - that includes angelfish, large cichlids, goldfish, and most predatory species. Even "peaceful" fish like pearl gouramis will eat a freshly moulted shrimp if they find one.

Amanos can be kept with dwarf shrimp (Neocaridina davidi, Crystal Reds) but will outcompete them for food if numbers are uneven. They don't predate other shrimp under normal conditions, though there are reports of starved Amanos harassing smaller shrimp.

The breeding reality - what most guides skim over

Females will carry eggs in a fully freshwater tank. You'll see a berried female with green or grey eggs clustered under her tail, and it's tempting to expect babies. They won't survive.

Caridina multidentata larvae are planktonic and require brackish water - salinity around 1.015-1.025 specific gravity - to develop through their larval stages. After metamorphosis, juveniles transition back to fresh water. In a standard community freshwater tank, larvae die within hours of hatching. This is not a deficiency in your setup; it's the species' natural life history.

Captive breeding is possible but requires a dedicated system: a freshwater breeding tank, a separate brackish rearing tank, a marine salt mix, and the ability to feed marine-grade phytoplankton and rotifers to larvae. It's genuinely specialist work and almost nobody does it by accident. The Amanos in the trade are almost entirely wild-caught from Japan and Taiwan. Buy healthy, active specimens from a reputable source rather than assuming your colony will self-sustain.

Moulting and health

Amanos moult regularly - roughly every four to eight weeks in good conditions, more frequently in younger or rapidly growing individuals. A freshly moulted shrimp is pale, soft, and vulnerable for several hours. This is normal. Don't remove the shed exoskeleton; shrimp often eat it for the minerals.

Failed moults - where a shrimp gets stuck in its old shell - are usually caused by iodine deficiency or sudden water parameter swings. Large water changes with significantly different temperature or chemistry can trigger a moult at the wrong time. Match your replacement water to tank temperature and consider using a mineral supplement designed for shrimp if you're seeing frequent failed moults in a soft-water setup.

Tracking parameters consistently over time makes it much easier to spot when something shifts. App-aquatic lets you log test results and flag trends across multiple tanks, which is useful if you're running a planted tank alongside a breeding setup.

Signs of a healthy Amano

Active grazing throughout the day. Translucent body with visible internal organs (a pinkish or olive-coloured patch along the dorsal line is the ovary in females - completely normal). Steady, purposeful movement. Healthy Amanos are rarely still during the day unless hiding during a moult.

Concerns: white, opaque, or milky body colouration (bacterial infection or ammonia stress), lethargic shrimp sitting at the surface (oxygen or ammonia problem), consistent jumping or glass-surfing (water quality issue, check parameters immediately).

How many Amano shrimp do you need?

For algae grazing in a community tank, work on roughly one Amano per 5-8 L (1.5-2 US gal) of planted volume, up to a sensible ceiling. A 100 L (26 US gal) planted community tank with moderate fish stocking handles 10-15 Amanos comfortably. More than that and you'll need to supplement feed them regularly because the tank won't produce enough natural grazing to keep them occupied and healthy.

There's no benefit to overstocking shrimp. Beyond a certain density they compete for food, the dominant individuals eat better than subordinate ones, and you end up with a stressed, hungry group rather than an efficient algae crew. Keep numbers proportionate and make sure your water changes stay consistent as bioload increases.