Amano Shrimp — Tank Size, Adult Size, Lifespan & Full Care Guide
Caridina multidentata
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Care requirements at a glance
| Scientific name | Caridina multidentata |
|---|---|
| Group | Invert |
| Adult size | 2 in (5.1 cm) |
| Minimum tank | 10 gallons |
| Temperature | 65-80°F |
| pH | 6.5-7.5 |
| Hardness | 6-20 dGH |
| Temperament | Peaceful |
| Social | Group (3+) |
| Diet | Herbivore |
| Swim level | Bottom |
| Care level | Easy |
| Lifespan | ~3 years |
How big do Amano Shrimp get? Adult size explained
Amano Shrimp sit in the classic community-fish size band. They are big enough to be visible from across a room, small enough that a standard 20-gallon tank gives them real swimming space. Adult amano shrimp reach 2.0 inches (5.1 cm). Fish you buy are almost always juveniles at roughly 0.9″, so plan the tank around the adult number, never the size in the bag.
| Stage | Typical length |
|---|---|
| Size sold in stores | about 0.9″ (2.3 cm) |
| Half-grown | 1.5″ (3.8 cm) at roughly 6 months |
| Full adult size | 2.0″ (5.1 cm) by 10 months |
| Sexual maturity | usually before full size, around 4–6 months |
Unlike fish, amano shrimp grow by moulting. You will periodically find a translucent empty shell in the tank — that is a healthy sign, not a dead animal. Leave it in; the calcium gets recycled.
Growth rate depends mostly on feeding quality and water changes in the first six months. Stunted growth from poor water does not make the fish 'stay small' safely — internal organs keep growing, which shortens lifespan considerably.
Amano Shrimp tank size: minimum vs recommended
Because amano shrimp produce very little waste, the 10-gallon minimum is about stability rather than bioload — small volumes swing in temperature and chemistry far faster.
Remember that the minimum tank and the minimum group interact. Amano Shrimp need at least 3 individuals, so the real question is not “will one fit in 10 gallons” but “will 3 of them fit”. That is why we recommend 20 gallons as the practical starting point.
| Tank size | Amano Shrimp it supports | Verdict |
|---|---|---|
| 5 gallons | — | Too small |
| 10 gallons | 9 in one group | Workable minimum |
| 20 gallons | 9 in one group | Comfortable |
| 29 gallons | 9 in one group | Comfortable |
| 40 gallons | 9 in one group | Comfortable |
| 55 gallons | 9 in one group | Comfortable |
| 75 gallons | 9 in one group | Comfortable |
Numbers assume amano shrimp are the main occupants with light additional stocking, a filter rated for the tank, and weekly 25–30% water changes. Use the stocking calculator to model a mixed community.
Amano Shrimp group size: how many should you keep together?
Amano Shrimp are a shoaling species. In groups below 3 they show measurable stress behaviour: faded colour, hiding, refusing food and darting at the glass. This is not a preference — it is how the species regulates its own sense of safety.
Minimum: 3. Better: 5–6. Colour and natural behaviour improve noticeably once the group passes about 7. If your budget forces a choice between more species and bigger groups, always choose bigger groups — a tank with two well-sized shoals looks far better than one with six lonely singletons.
Amano Shrimp water parameters
| Parameter | Range | Notes |
|---|---|---|
| Temperature | 65–80°F (18–27°C) | aim for 72°F and keep it stable |
| pH | 6.5–7.5 | target 7.0; stability beats the exact number |
| Hardness (GH) | 6–20 dGH | moderate to hard |
| Ammonia (NH₃) | 0 ppm | any reading means the tank is not cycled |
| Nitrite (NO₂) | 0 ppm | any reading is an emergency — water change now |
| Nitrate (NO₃) | under 20–40 ppm | controlled by water changes and live plants |
This species tolerates — and in fact prefers — harder water, which makes it a good match for most municipal tap water in the UK, US Midwest and much of Europe.
Stability matters more than perfection. A tank sitting steadily at pH 7.7 is healthier than one swinging between 6.5 and 7.5 every week. Test your tap water first, then choose fish that match it, rather than buying the fish and fighting the water afterwards.
Ideal amano shrimp tank setup
A 10-gallon tank with a group of 3+ and peaceful tankmates. Provide hiding spots and algae-covered surfaces. They are excellent cleanup crew members.
| Substrate | Dark substrate brings out colour; the choice is otherwise up to you. |
|---|---|
| Planting | Heavily planted with broad leaves and moss. Plants are not decoration for this species — they are cover, grazing surface and a stress buffer. |
| Flow | Gentle. Baffle the filter outflow if the fish are being pushed around. |
| Lighting | Moderate. Floating plants diffuse the light and make shy fish bolder. |
| Lid | Recommended — it also reduces evaporation and heat loss. |
What do Amano Shrimp eat? Diet and feeding
Excellent algae eaters — consume hair algae, diatoms, and leftover food. Supplement with algae wafers and blanched vegetables. Feed small amounts 1 time daily.
The single most common feeding error is quantity, not quality. Amano Shrimp have a stomach roughly the size of their eye. Feed what disappears in about two minutes, once a day, and the tank stays clean.
Staple: high-quality algae wafer or spirulina-based pellet.
- Blanched courgette, cucumber or spinach twice a week
- Repashy-type gel food
- Established biofilm and soft green algae
| Frequency | What to do |
|---|---|
| Daily | One small feeding of high-quality algae wafer or spirulina-based pellet. Everything eaten within 2 minutes. |
| 2–3× weekly | Rotate in a second food type for variety and micronutrients. |
| Weekly | One fasting day gives the gut time to clear. Skip this for fry and for shrimp. |
Amano Shrimp behaviour and temperament
Amano Shrimp are peaceful and will not start trouble. Their weakness is the opposite — they are easily bullied or outcompeted for food by faster or bolder species. They spend most of their time in the substrate and lower third.
Signs of a settled, healthy specimen: strong colour, fins held open, active foraging, and a normal reaction to your hand near the glass. Signs of a stressed one: clamped fins, faded colour, hovering in a corner, gasping at the surface, or hiding constantly during daylight hours.
How long do Amano Shrimp live?
| Factor | Effect on lifespan |
|---|---|
| Stable, cycled water | Adds years. The most common cause of early death in amano shrimp is ammonia exposure in an uncycled tank. |
| Correct temperature | Running warmer than 80°F speeds metabolism and shortens life; running cold invites disease. |
| Varied diet | Single-food diets cause organ problems and colour loss over time. |
| Right group size | Chronic stress from wrong social setup measurably shortens lifespan. |
| Genetics | Mass-bred stock from large farms often lives noticeably shorter than quality or local stock. |
Amano Shrimp tank mates: what works and what does not
Compatibility is decided by four things, in this order: water parameters (65–80°F, pH 6.5–7.5), adult size, temperament, and swimming level. A fish that matches on three and fails on one is not a match.
Good tank mates
Avoid these
Check any pairing in the compatibility tool →
Breeding amano shrimp
Cannot breed in freshwater — larvae need brackish water. Most amano shrimp are wild-caught. They do not overpopulate freshwater tanks.
If you want fry to survive, the practical route is a separate, gently filtered grow-out tank. In a community tank almost every egg or fry becomes food, which is normal and not a sign that anything is wrong.
Male vs female amano shrimp
Males are smaller (1.5") with a dotted pattern. Females are larger (2") with a dashed pattern. Females carry green eggs under the belly.
Amano Shrimp health, diseases and prevention
| Problem | What you see | What to do |
|---|---|---|
| Ich (white spot) | Salt-grain white dots, flicking against decor | Raise temperature slowly to 82°F and treat; do NOT use salt or copper with this species. |
| Fin rot | Ragged, receding or blackened fin edges | Almost always water quality. Increase water changes before reaching for medication. |
| Bloat / constipation | Swollen belly, stringy white waste | Fast 2–3 days, then feed blanched deshelled pea or daphnia. |
| Bacterial infection | Red streaks, ulcers, lethargy | Quarantine and treat with a broad-spectrum antibacterial; review water quality. |
| Stress / chronic hiding | Faded colour, clamped fins | Check parameters, group size and tank mates before medicating. |
| Failed moult | Stuck partial shell, sudden death after moulting | Usually unstable GH. Keep hardness steady and supplement calcium. |
Prevention beats treatment every time: quarantine new arrivals for two weeks, keep the tank understocked rather than at maximum capacity, and do a consistent weekly water change instead of a large emergency one every month.
First 30 days with Amano Shrimp: a practical checklist
Most losses happen in the first month, and almost all of them are avoidable. This is the schedule we recommend.
| Before you buy | Do not add amano shrimp to a tank younger than about six months. They need established biofilm to graze. A cycled tank is the single biggest predictor of whether these animals survive. |
|---|---|
| Day 1 — acclimation | Float the bag 20 minutes to match temperature, then drip acclimate over 45–60 minutes. Drip acclimation is mandatory for invertebrates, not optional. |
| Days 1–3 | Lights off or dimmed. Do not feed on day one. Expect hiding and pale colour; this is normal. |
| Days 4–14 | Test ammonia and nitrite every second day — new stock is the classic trigger of a mini-cycle. Feed lightly. Watch that every individual is eating. |
| Days 14–30 | Colour should be full and behaviour settled. This is the window where starvation typically shows up — check body condition from above, not just from the side. |
| After day 30 | Now you can add the next species. Adding stock in stages rather than all at once is what keeps the filter ahead of the bioload. |
Common mistakes when keeping Amano Shrimp
- Buying 1 instead of 3 — The most common mistake with this species. An under-sized group is a permanently stressed group, and stress is what makes fish susceptible to everything else.
- Adding stock to an uncycled tank — Ammonia burns gills permanently. Cycle first, always — see our tank cycling guide.
- Overfeeding — Uneaten food becomes ammonia. Two minutes, once a day is the rule.
- Chasing pH with chemicals — pH adjusters cause swings that are far more dangerous than a stable pH slightly outside 6.5–7.5.
- Using medication containing copper — Lethal to shrimp and snails. Read every label, including plant fertilisers.
What does a amano shrimp setup cost?
| Item | Typical cost |
|---|---|
| Aquarium, 20 gal | $64 |
| Filter | $25 |
| Light | $25 |
| Substrate & decor | $28 |
| Liquid test kit | $32 |
| 3× amano shrimp | $24 |
| Estimated total | $198 |
Indicative US retail prices for a new setup. Running cost is modest: mostly electricity for the filter, plus food and a water conditioner. Buying a larger tank up front is almost always cheaper than upgrading twice.
Amano Shrimp compatibility: verdict per tank mate
Each pair below is a full comparison of temperature, pH, adult size and temperament. Green means compatible, amber means workable with conditions, red means avoid.
Open the full compatibility matrix
Amano Shrimp FAQ
What size tank do amano shrimp need?
The minimum tank size for amano shrimp is 10 gallons (37 litres). Because they need a group of at least 3, we recommend 20 gallons or larger for a healthy long-term setup.
How big do amano shrimp get?
Adult amano shrimp reach 2.0 inches (5.1 cm). Store specimens are usually juveniles at around 0.9 inches, so always plan the tank around the adult size.
How long do amano shrimp live?
Amano Shrimp typically live about 3 years in a well-maintained aquarium. Stable water quality and a varied diet are the two biggest factors in reaching the upper end of that range.
How many amano shrimp should I keep together?
Keep at least 3 together. Groups of 5 to 6 show noticeably better colour and more natural behaviour. Below 3 they become stressed, hide and lose colour.
What water parameters do amano shrimp need?
Keep amano shrimp at 65–80°F (18–27°C), pH 6.5–7.5, and hardness 6–20 dGH. Ammonia and nitrite must both read zero at all times.
Are amano shrimp good for beginners?
Yes. Amano Shrimp are rated easy to keep and are a solid choice for a first tank, provided it is fully cycled before they go in.
What do amano shrimp eat?
Excellent algae eaters — consume hair algae, diatoms, and leftover food. Supplement with algae wafers and blanched vegetables. Feed small amounts 1 time daily.
Do amano shrimp need a heater?
No. Amano Shrimp tolerate temperatures down to 65°F and can be kept at room temperature in most homes, which makes them one of the few genuinely unheated-tank species.
Do amano shrimp need a filter?
Yes. A filter houses the bacteria that convert ammonia to nitrate. Use a gentle sponge filter or cover the intake — strong suction and small invertebrates do not mix.
Can amano shrimp live alone?
They can survive alone but should not be kept that way. Amano Shrimp are a shoaling species and a lone individual is a chronically stressed one, which shortens its life.
What fish can live with amano shrimp?
Good tank mates include Neon Tetra, Cardinal Tetra, Guppy, Endler's Livebearer, Platy, Dwarf Gourami. Match water parameters first, then temperament, then adult size — anything that can fit them in its mouth eventually will.
What should you not keep with amano shrimp?
Avoid Discus. These are either large enough to eat them, aggressive enough to harass them, or need water parameters too far outside 65–80°F and pH 6.5–7.5.
Are amano shrimp aggressive?
No. Amano Shrimp are peaceful and will not harass other fish. The risk runs the other way — they are easily bullied or outcompeted for food.
How do you tell male from female amano shrimp?
Males are smaller (1.5") with a dotted pattern. Females are larger (2") with a dashed pattern. Females carry green eggs under the belly.
Do amano shrimp breed in a home aquarium?
Cannot breed in freshwater — larvae need brackish water. Most amano shrimp are wild-caught. They do not overpopulate freshwater tanks.
Why are my amano shrimp hiding or losing colour?
In order of likelihood: the tank is not fully cycled (test ammonia and nitrite), the group is too small, the temperature is unstable, or a tank mate is harassing them. Fading colour is the earliest visible stress signal in this species — test the water before treating for anything.
How much does an amano shrimp setup cost?
Expect roughly $198 for a complete new 20-gallon setup including tank, filter, light, substrate, a test kit and the animals themselves. Buying the right size once is cheaper than upgrading twice.