Amano Shrimp Breeding: A Step-by-Step Guide to Raising Larvae

1. Why Are Amano Shrimp Difficult to Breed in Freshwater?

Adult Caridina multidentata live, mate and carry their eggs in freshwater. A newly hatched zoea is a small larva suspended in the water. In nature, current carries larvae towards environments connected with the sea. After developing into juveniles, they return towards freshwater. This is an amphidromous life cycle.

Neocaridina hatch looking like miniature adult shrimp rather than undergoing the same free-swimming larval phase. The Neocaridina care guide provides a useful comparison.

• Egg development: The embryo develops inside an egg carried by the female.

• Hatching: The larva leaves the egg; this is the first production milestone.

• Zoeal development: A larva feeds in the water and grows through moults.

• Metamorphosis: The transition to a small shrimp capable of settling securely.

• Juvenile: A young, not yet adult shrimp that moves and grows in shrimp form.

Keep adult water and larval rearing water separate. Saline larval development is not a reason to add marine salt to the adult freshwater aquarium. Maintain the berried female in freshwater.

2. Equipment to Prepare Before Breeding

Searching for food cultures and a salinity meter after hatching is usually too late. First establish which rearing method you can actually maintain. A bag of salt and a container of green-looking water are not a complete preparation.

• Mature freshwater aquarium: A safely filtered, sheltered system for adults and the berried female.

• Separate larval containers: Clean vessels with known working volumes appropriate to the method. Individual research cultures and communal tanks differ.

• Collection tools: A wide-bore pipette, soft tubing, a white inspection container and a way to control suction.

• Air pump and valve: Gentle circulation for a communal tank, with suitable protection against back-siphoning.

• Heater, thermometer or controlled water bath: Small pilot containers are temperature-controlled from outside rather than fitted with an internal heater.

• Salinity instrument: A seawater-scale refractometer or a calibratable conductivity-salinity meter. A freshwater TDS pen is not equivalent.

• Marine aquarium salt, mixing container and scale: For preparing replacement water away from the larvae.

• Food cultures and counting equipment: Identified microalgae and, when required by the chosen method, rotifers. A microscope and counting chamber allow density checks.

• Lighting, magnification and maintenance tools: Enough light to inspect animals and equipment dedicated to this system.

How large should the larval container be?

About thirty litres is NeoMa's example for planning a communal home setup. This is a space-and-equipment example, not an experimentally validated stocking density or guarantee of success. The Logemann brothers report home rearing in 30–54-litre aquaria. In contrast, the numerical Kondo pilot described below uses very small individual culture vessels. Do not copy the stocking density from one system into the other. Lee's abstract reports a density effect on survival above twenty larvae per 500 mL; this is not a recommended home stocking level.

For a first attempt, work with a countable group that matches your food and maintenance capacity rather than placing every hatchling in one container. Record actual water volume alongside larval numbers. If you divide a batch, retain the maternal identity and hatch date for each group.

Mechanical filtration and air stones

Strong intakes can capture larvae. In a communal aquarium, use gentle circulation rather than an air setting that continually tumbles animals or traps them among bubbles. The Logemann report describes better results with an open airline; that observation does not establish that every air stone harms every larval system. Do not confuse the individual pilot's water-renewal method with a larger aerated tank.

3. Recognising and Monitoring a Berried Female

Females are generally larger than males, broader underneath and more dash-marked along the flanks. Distinguish the ovarian saddle behind the head from eggs carried beneath the abdomen. A berried female holds numerous small eggs among her swimming legs and moves them to ventilate the clutch.

Eggs may become paler as development proceeds, with eye spots visible near hatching. Brief photographs from a similar angle help track changes. Colour alone is not a fertility test; lighting and viewing angle affect what you see.

How long do eggs take to hatch?

Around three to five weeks is a useful observation window in husbandry reports; some care accounts give four to six weeks. Temperature and the unknown age of the eggs when first noticed affect the interval. Record the first observation and check during evenings and mornings as development progresses rather than relying on a fixed day-28 alarm.

Separating the female is optional. Where fish would eat hatchlings, a mature separate freshwater hatching aquarium can simplify collection. If a move is necessary, plan one calm transfer into a prepared tank instead of repeated capture, particularly near hatching.

4. Collecting the Larvae

Hatching is often noticed at night and may occur in several batches. Look in the morning for small, transparent comma-shaped animals suspended in the water. Prepared larval water and food must already be available before collection starts.

1. One breeder method reduces room and aquarium illumination, then uses a small light directed at a corner to see whether larvae concentrate there.

2. Collect visible animals with a wide-bore pipette or soft tubing at low suction into an inspection container. Do not force larvae through a narrow tip or start a siphon by mouth.

3. If circulation is briefly reduced for collection, maintain gas exchange and check that equipment is operating afterwards. Avoid leaving the main tank unfiltered for a prolonged period.

4. Keep larvae submerged, label the hatch date and approximate number, and move them into prepared rearing water. The mother does not belong in the saline larval vessel.

Light does not produce one universal response. Corner-light collection is a Logemann husbandry observation. Araki, Ideguchi and Hamano's 2021 experiment found early zoeae moving downwards in light and dispersing through the water column in darkness. Directional spot lighting and general illumination are different conditions. No universal lux setting or promise that every larva rises to the surface is given here. If concentration fails, collect visible larvae calmly rather than continually increasing light intensity.

5. Preparing the Larval System

1. Clean the vessel: Leave no detergent or disinfectant residue, and separate its tools from those of the adult aquarium.

2. Mix water elsewhere: Use an appropriate source, marine salt and salinity measurement. Do not pour undissolved salt onto larvae.

3. Stabilise heat and circulation: Confirm actual temperature and use gentle aeration in a communal setup.

4. Set the light schedule: Consider algal production separately from larval illumination. Continuous strong light is not automatically necessary.

5. Verify food in advance: Have identified, healthy cultures, measurable densities and a backup.

6. Record density: Note actual water volume, starting larval count and rearing method together.

7. Take baseline measurements: Check temperature, salinity, ammonia/ammonium and nitrite using tests appropriate to saline water.

Clear newly mixed seawater is not necessarily ready until it has been measured. Do not start assembling the system after hatching. Mature biological filtration does not appear overnight; plan the chosen method's water-renewal workload beforehand.

6. What Salinity Should Amano Larvae Be Raised At?

The numerical reference in this guide is the 26 °C and 25.5 ppt combination tested by Kondo and colleagues. It is one experimental treatment, not an average of unrelated studies or a universal ideal. Read it together with the feeding and maintenance conditions below. Do not substitute Lee's result from a different system into this method.

What did the sources actually compare?

Larvae remaining alive for a time and larvae completing metamorphosis are different outcomes. Selecting one attractive number from each study's food, density and water regime does not create a newly validated best recipe.

Understanding ppt, PSU and specific gravity

ppt means parts per thousand; in a mass-based description it represents grams per kilogram. PSU refers to the practical salinity scale, which is technically dimensionless. Numbers may be close for seawater measurements, but record the instrument's scale. Specific gravity, or SG, is a density ratio with a temperature reference. A salinity of 25 ppt is not SG 1.025. A general TDS pen's ppm reading is not a ppt measurement either.

Choose the correct salt and prepare water separately

Use a balanced salt mix intended for marine aquariums. Sodium chloride alone does not reproduce seawater's ionic composition; table salt and culinary sea salt are not equivalent products.

Place a measured volume of source water in a separate container, dissolve salt according to the product's mixing instructions, stabilise temperature and check salinity with a correctly calibrated instrument. Correct the batch in the mixing container instead of adjusting salt directly around larvae. Do not automatically equate a label's grams-per-litre dose with a measured ppt value.

7. What Do Larvae Eat During Their First Days?

Identified microalgae are among the researched first foods, and some successful systems also use small rotifers. An adult eating an algae wafer does not establish that a new larva can use the same food.

A sourced example feeding and maintenance sequence

The Kondo reference uses six-well culture plates, with one larva in each 8 mL water volume. Live Tetraselmis is supplied at 1 × 10⁵ cells/mL and rotifers at 20 individuals/mL. The photoperiod is fourteen hours light and ten hours dark. Each morning, the larva is moved to a clean well with new water and food. These are individual research-culture conditions, not a tested recipe copied directly into a thirty-litre communal aquarium.

1. Before hatching: Confirm both food identities, densities and ongoing supply. A bottle obtained only on hatch day is not a dependable culture plan.

2. Initial placement: Begin with prepared rearing water and food rather than deliberately waiting to test starvation endurance.

3. Daily maintenance: Follow the selected pilot's renewal routine and record movement, food availability and losses.

4. Through development: Do not change feed solely because a calendar day has arrived. Maintain the chosen regimen and assess development alongside water quality.

Hamasaki and colleagues' 2020 feeding experiments support the role of cultured algae and rotifers. Preserved algae or another single feed should not be substituted on the assumption of identical results. Lee's abstract finding about microalgal first food likewise belongs within that experiment's conditions.

Prepare the microalgal culture beforehand

A microalgal culture grows identified algae under suitable conditions. It is not the same as unidentified green water. Green colour does not verify cell size, nutritional value or culture health.

• Obtain a reliable starter and its species-specific culture instructions.

• Use clean containers and dedicated tools; avoid sharing tubing or pipettes among cultures.

• Provide suitable salinity, light, mixing and culture medium. Do not treat the medium as fertiliser to pour directly into the larval tank.

• Keep a backup and avoid consuming the entire stock when larval demand begins.

• Track density by cell counts rather than colour alone.

• Sudden clearing, sediment, odour or unwanted organisms under the microscope suggest culture collapse or contamination; withhold that culture.

The FAO live-food manual provides a foundation for culture management. Changing algal species can change the food value represented by the same cell count.

Can Artemia nauplii be used?

Artemia nauplii are not recommended here as a verified sole starting diet for newly hatched Amano larvae. Prey size and capture success matter, and no sourced switch-day covering every later larval stage has been established for this guide. The numerical example uses rotifers, not Artemia. Feeding post-metamorphic juveniles is a separate stage.

The Artemia hatching guide explains food production; it does not independently establish suitability for Amano larvae.

Recognising inadequate or excessive feeding

Stalled growth, prolonged development, weak movement and increasing losses warrant investigation, but appearance alone does not diagnose starvation. Confirm actual food availability through counting and observation, then test the water. Excess feed can increase ammonia, bacterial load and oxygen demand. Adding more food without measurement is not the answer.

8. Maintaining Water Quality in the Larval System

Evaporation removes water while leaving most salt behind. Mark the starting level, restore evaporative loss with suitable freshwater and measure after mixing. Repeated saline top-ups raise salinity. Water removed by siphoning contains salt, so replace it with water prepared to the same salinity.

Record temperature and salinity regularly and use saline-compatible ammonia/ammonium and nitrite tests. Interpret ammonia alongside pH and temperature. Odour, cloudiness and inactivity do not replace measurements. If conditions deteriorate, investigate the food supply and aeration too.

How often should water be changed?

The individual research pilot uses the daily clean-container routine described above. That is not an instruction to drain every communal larval aquarium each day. The Logemann communal-tank report includes partial water changes, but its schedule cannot automatically be transferred to a different feeding load.

In a communal tank, remove settled waste with low suction while keeping larvae visible. Inspect siphoned water in a white container before discarding it. Any intake guard needs openings appropriate to the developmental stage and must not trap or crush animals. Match temperature and salinity outside the aquarium. Avoid drying larvae in a net or exposing them to air during maintenance.

9. How Does Temperature Affect Breeding Success?

Ohara and colleagues examined adult reproductive output at 20, 23 and 26 °C in 2024. In Amanos, the number of newly hatched larvae per female decreased as temperature increased, with low hatching success at 26 °C. This was not an experiment determining larval rearing temperature through metamorphosis.

Do not continually heat the adult aquarium to force higher production. Equally, do not convert that adult result directly into a new larval temperature target. The larval example here takes its temperature from its own source experiment rather than averaging it with Lee's 24 °C result. Maternal condition, egg quality and larval development are separate assessment stages.

10. Following Larval Development

A new larva looks like a tiny transparent comma suspended in the water and makes short swimming movements. It should not be expected to walk continuously on the floor like an adult. Watching size, appendages and behaviour in the same individuals under magnification is more useful than simply counting moving specks.

Hayashi and Hamano's morphological study describes nine zoeal stages. Counting every moult accurately at home is difficult. With metamorphosis, body form and movement approach those of a small shrimp: it settles steadily using walking legs and swims directionally using its swimming legs. A brief contact with glass or a lighter colour alone is insufficient.

How long until they become juvenile shrimp?

Plan for approximately a month, potentially longer. Hayashi and Hamano's abstract reports about a month. Food and temperature can change development rate, and a batch may include late developers. Do not move the whole group to freshwater because thirty days have elapsed. Investigate food and water when development stalls instead of relying only on increased heat.

11. Returning Young Amanos to Freshwater

Begin with juveniles whose completed metamorphosis is supported by both behaviour and appearance. Leave siblings still showing larval form in their rearing system. The whole batch need not be ready together.

The Logemann brothers report direct transfer of completed juveniles and describe a gentler alternative: replace fifty percent of the water in a separate container with freshwater, then transfer after about one hour. This is their husbandry method, not a universally tested safe rate for every initial salinity. Reaching the juvenile stage in Kondo's experiment does not independently validate that freshwater-transfer method.

1. Prepare a freshwater grow-out aquarium with mature biological filtration, a protected intake and accessible grazing surfaces.

2. Move completed juveniles into a separate transition container using a wide-bore tool, leaving larvae behind.

3. Match temperature and record actual salinity while following the chosen sourced transfer method. A small initial group allows closer observation without exposing the entire batch at once.

4. Preserve water quality and oxygenation during any extended wait. Do not continue automatically if animals lose balance or cannot grip surfaces.

5. Record settlement, grazing and subsequent growth in freshwater. Do not invent a daily ppt-reduction schedule.

A fish-free grow-out tank with accessible biofilm simplifies monitoring. Transfer juveniles with little transport water rather than pouring saline water into the main freshwater aquarium.

12. Common Breeding Mistakes

1. Salting the adult aquarium: Exposes adults and companions to unsuitable changes. Use a separate larval system.

2. Preparing containers after hatching: Delays first care and feeding. Start preparation when eggs are noticed.

3. Starting without food cultures: Correct salinity does not provide nutrition. Have the cultures and a backup ready.

4. Confusing TDS with salinity: The wrong unit leads to incorrectly prepared water. Use seawater-appropriate equipment.

5. Ignoring calibration: A precise-looking display is not evidence of accuracy. Follow the instrument instructions.

6. Strong filter suction: Can capture larvae or press them against a guard. Adjust flow under observation.

7. Overfeeding: More food can worsen the water. Check availability and consumption.

8. Topping evaporation up with saline water: Accumulates salt. Use suitable freshwater for normal evaporation.

9. Premature freshwater transfer: Does not meet the larval stage's requirements. Confirm metamorphosis.

10. Calling hatching a complete success: Conceals later losses. Count juveniles that keep growing in freshwater.

13. A Breeding Log and Meaningful Success Measures

Track each hatch as a separate batch in the NeoMa aquarium journal. The first date a berried female was seen may not be the spawning date; write unknown when appropriate. Do not label an estimated larval count as an exact measurement.

Fifty is an example journal entry, not a stocking recommendation. Follow three separate outcomes: juveniles produced from the initial larvae, survival after freshwater transfer and continued growth afterwards. Mark percentages as approximate when their starting count is estimated.

Read the Amano care guide for adult requirements and the pH, KH and GH guide for water chemistry concepts. A guide to preparing RO water and minerals for shrimp aquariums is also in preparation.

14. Frequently Asked Questions

Can Amano shrimp breed in freshwater?

Mating and hatching can occur there. Successful larval rearing needs a separate saline phase; an ordinary freshwater aquarium should not be expected to produce a population boom.

How long do eggs take to hatch?

Begin with a three-to-five-week observation window; some sources report four to six weeks. Temperature and egg age when first noticed affect the interval.

Why do larvae need saline water?

To complete the sea-connected developmental phase of their natural life cycle. Adults have different care needs.

Can table salt be used?

It is not recommended. Use a balanced marine aquarium mix and measure the finished water.

Do Amano larvae eat Artemia?

It is not recommended here as a verified sole first feed. The sourced example uses microalgae and small rotifers; no universal Artemia switch-day is established for all stages.

How long do larvae take to grow?

Transformation into juveniles may occur around a month but can take longer. Developmental stage takes priority over elapsed days.

When can young Amanos move into freshwater?

After completed metamorphosis is supported by steady settlement and shrimp-like directional movement, rather than age or colour alone.

Must the berried female be isolated?

No. A prepared separate freshwater hatching tank can help where fish would eat larvae. The female must not be placed in saline larval water.

Why is breeding difficult?

Eggs, larvae, metamorphosis and freshwater transfer require different management. A continuing food supply and precise water monitoring are necessary.

Can it be done at home?

Yes. A small, documented trial is more manageable than testing an unmeasured mixture of methods on the entire batch.

Sources and Access Scope

• Kondo, Hamasaki & Dan (2021), Crustacean Research 50:41–54; DOI 10.18353/crustacea.50.0_41 — full-text methods and relevant larval results checked; source of the numerical pilot.

• Lee, Hung-Wen (2009), Larviculture of Caridina multidentata — university-record abstract consulted, without claiming examination of the complete thesis method.

• Ohara et al. (2024), Aquatic Animals; DOI 10.34394/aquaticanimals.2024.0_AA2024-5 — full-text adult-reproduction methods and relevant results checked.

• Hamasaki et al. (2020), DOI 10.18353/crustacea.49.0_225 — relevant methods and results of the live algae/rotifer feeding comparison.

• Hayashi & Hamano (1984), Zoological Science 1(4):571–589 — accessible abstract for zoeal stages and development time.

• Araki, Ideguchi & Hamano (2021), Response to light in first and second stage zoeae of eight freshwater shrimps — institutional abstract for limits to the light-response interpretation.

• Frank & Carsten Logemann: Amano breeding report — direct breeder observations for communal volume, collection and juvenile freshwater transfer, distinguished from controlled research.

• FAO, Manual on the Production and Use of Live Food for Aquaculture, section 2.3 — microalgal culture management.

• NOAA: Specific gravity, salinity and temperature conversion report — salinity scales and temperature-dependent density conversion.

This guide was written by NeoMa Aquatics. Original: https://neomaaquatics.com/en/guides/amano-shrimp-breeding