Ring-Necked Shrimp (Macrobrachium assamense)

Understand the animal and the offer

Ring-Necked Shrimp is the common name used here for Macrobrachium assamense. The World Register of Marine Species accepts that scientific name and places the animal in Palaemonidae within Decapoda. This identity distinguishes it from Amano, cherry and other aquarium shrimp sold under different scientific names.

An encyclopaedic summary of Macrobrachium assamense describes it as a freshwater shrimp first described in 1958. Choose it as a living freshwater invertebrate with its own identity, rather than assuming that care instructions for every shrimp carrying a similar trade name will apply without adjustment.

Read the listed dispatch size as the offer contract

A 2 cm animal and a 4 cm animal both fit the stated dispatch grade. Measure aquarium suitability by water quality, filtration, cover and the space needed as the animal continues to grow, rather than choosing a setup that only accommodates its arrival size.

Sex is guaranteed only when the selected option explicitly states male or female. This Ring-Necked Shrimp listing has no sex-guaranteed option.

The gallery images are representative of this type of animal rather than photographs of the exact animal supplied, so colours can look slightly different from the live animal.

For other freshwater invertebrates, browse the current shrimps and crustaceans collection and compare the care needs attached to each named animal.

Choose water and space before ordering

OATA’s freshwater shrimp and snails guidance gives 17–27°C, pH 6.5–8.0 and general hardness of 4–18°dH for the group. These are broad figures rather than a target unique to Macrobrachium assamense. It also sets ammonia and nitrite at zero mg per litre and says nitrate should not exceed 20 mg per litre above the normal tap-water level.

Test the aquarium before choosing the animal. A temperature inside the range is not enough when ammonia or nitrite is detectable, and a suitable pH does not compensate for an immature filter. Stability, waste processing and conditioned replacement water must work together.

Use space to protect stability

OATA recommends an aquarium of at least 10 litres for a group of small freshwater shrimp or snails and approximately 20 litres for larger animals such as Amano shrimp. It advises using a larger aquarium when fish are included and notes that larger volumes normally give more stable temperature and water quality.

Those group figures are starting points, not a species minimum for this animal. Do not classify Ring-Necked Shrimp as permanently small from its 2–4 cm dispatch grade. Select as large an aquarium as reasonably possible, include a filter in every setup and leave enough usable space for shelter, feeding and observation. If fish or additional shrimp are planned, complete the compatibility screen before treating the basic volume as sufficient.

• Proceed: the aquarium is mature, filtered, covered with shelter and already holds the target water values.
• Pause: ammonia or nitrite is detectable, temperature fluctuates or the filter has not matured.
• Re-plan: the proposed mixed setup relies on the aquarium’s litre figure alone to prevent predation.

Mature the filter before introduction

A filter is essential because livestock waste introduces ammonia into the aquarium. The RSPCA’s aquarium welfare guidance explains that a working biological filter supports bacteria that convert toxic ammonia into nitrite and then into the safer nitrate form. For Ring-Necked Shrimp, both ammonia and nitrite must test at zero mg per litre before introduction.

Prepare the biological system

1. Install the aquarium, substrate, filter and chosen cover before adding the shrimp.
2. Mature the biological filter until testing repeatedly shows zero ammonia and zero nitrite.
3. Confirm that temperature remains within 17–27°C and that pH remains within 6.5–8.0.
4. Check the filter for blockages and make sure water continues to circulate through its media.
5. Add livestock slowly so the bacterial population has time to respond to increased waste and feeding.

Stocking too quickly can create new tank syndrome: the biological filter cannot process the increased waste, allowing ammonia or nitrite to rise. A clear-looking aquarium can still have unsafe dissolved waste, so use test results rather than appearance as the decision.

Use our freshwater shrimp keeping guide to organise aquarium preparation before livestock arrives. Complete the setup first; moving a shrimp into a newly assembled aquarium and waiting for the filter to catch up exposes it to avoidable waste changes.

Once the system is mature, keep stocking changes small. One purchase adds one animal, but every new animal and every increase in feeding adds work for the biological filter. Test after changes rather than assuming that past stability guarantees the next week.

Hold the water range steady

Keep Ring-Necked Shrimp between 17°C and 27°C, with pH from 6.5 to 8.0, general hardness from 4 to 18°dH and carbonate hardness from 3 to 15°dKH. Use these values as boundaries for a stable freshwater aquarium rather than changing the water repeatedly to hit the numerical midpoint.

The midpoint of the temperature range is 22°C, but that calculation does not make 22°C a preferred setting. Likewise, the midpoint of pH 6.5–8.0 is 7.25, yet pH is logarithmic and should not be adjusted simply to match an average. Choose a stable point within the stated range that also suits every animal in the aquarium.

Test values in a useful order

1. Check ammonia and nitrite first; both must be zero mg per litre.
2. Check nitrate against the normal tap-water level and keep the aquarium increase to no more than 20 mg per litre.
3. Compare aquarium temperature and pH with their established pattern.
4. Track general and carbonate hardness so replacement water does not create an abrupt shift.

Our water chemistry guide explains what the principal tests measure and why each value affects aquarium decisions. Record results with dates so a gradual change is easier to see than it would be from isolated readings.

Enter measured values into the water matcher to compare the aquarium with the stated guidance. Always work from actual test results; products intended to alter pH or hardness should not be added by guesswork.

Provide cover and a practical floor

Use aquarium gravel or sand and include places where the shrimp can shelter. Live plants are ideal for adding cover and grazing surfaces. Where live plants are not used, plastic aquarium plants and suitable ornaments such as model caves or plant pots can provide alternatives.

Arrange the aquarium so the animal can enter shelter without disappearing from routine care. You still need to confirm normal movement, feeding and appearance, so balance enclosed retreats with clear areas where food and waste can be seen.

Build the layout around daily decisions

A larger aquarium normally gives more stable environmental conditions, but its space still has to be usable. An empty floor offers little cover, while a completely enclosed layout can hide uneaten food and delay recognition of a health change. Place shelter around the aquarium while retaining access for siphoning and observation.

Consider the other inhabitants before deciding that a decorated setup is large enough. OATA advises increasing aquarium size when shrimp are kept with fish. Cover may reduce exposure, but it does not make a fish safe when the shrimp can fit in its mouth or when the fish is known to be predatory.

• Before introduction: install the substrate and shelter, then allow the filter to mature with the finished layout in place.
• At feeding: place food where the shrimp can reach it and where leftovers can be found.
• During maintenance: siphon accessible solid waste without stripping away every covered area.
• When behaviour changes: check whether another inhabitant is preventing access to shelter or food.

Choose decorations made for aquarium use and position them securely. The practical aim is a filtered freshwater environment with cover, visible feeding areas and enough room to maintain stable conditions.

Feed small, measured portions

For feeding, follow OATA’s group guidance for freshwater shrimp and snails. It describes them as generally herbivorous animals that graze algae in the aquarium, then advises supplementing that grazing with algae wafers or commercial pellets made for freshwater shrimp.

Offer food two or three times a week. Leave pellets or wafers for at least 30 minutes so the shrimp has time to find and eat them. Observe the animal rather than adding another portion simply because food was not taken immediately.

Use the first portion as a measurement

Algae growing in the aquarium contributes grazing, but it does not remove the need to provide a measured food source. Equally, feeding extra wafers to compensate for a newly cleaned surface can create waste if the shrimp does not consume them.

Overfeeding allows uneaten food to break down and release harmful waste. That creates extra demand on the biological filter and can raise ammonia, nitrite or nitrate. Portion control therefore protects both nutrition and water quality.

1. Choose an algae wafer or freshwater-shrimp pellet.
2. Place a small portion where the animal can reach it.
3. Allow at least 30 minutes for feeding.
4. Check whether food was eaten, guarded by another inhabitant or left untouched.
5. Remove persistent leftovers before they decay.
6. Record a reduced portion for the next scheduled feed when waste remains.

Do not feed more often as a substitute for observation. A consistent two- or three-times-weekly schedule, combined with visible portion checks, gives a clearer picture of appetite and prevents food from accumulating unnoticed among plants or ornaments.

Use a weekly maintenance routine

Carry out a partial water change of 25% at least once every week. Treat replacement tap water with a conditioner that removes chlorine or chloramine before it enters the aquarium, and avoid creating an abrupt change in the established temperature or water chemistry.

Work through the same sequence

1. Test ammonia, nitrite and nitrate before maintenance so the results describe the aquarium’s condition.
2. Remove approximately one quarter of the aquarium water.
3. Use a siphon to remove accessible solid waste from gravel or sand.
4. Check the filter for blockages and reduced flow.
5. Condition replacement tap water before adding it.
6. Refill carefully and confirm that the equipment resumes normal operation.
7. Record the test results and any change in the shrimp’s behaviour or appearance.

Test the water at least weekly even when the aquarium looks clear. Ammonia and nitrite are dissolved and cannot be judged by sight. Keeping a dated record also shows whether nitrate is gradually rising between water changes.

Do not rinse mature filter media under tap water. Chlorine or chloramine may kill part of the beneficial bacterial population that processes aquarium waste. Cleaning the media lightly in removed aquarium water reduces bacterial loss while allowing blockages to be cleared.

Weekly maintenance is also the time to check food accumulation beneath cover. Remove persistent leftovers without stripping away every grazing surface. The aim is a repeatable routine that controls solid waste, protects the biological filter and keeps the stated water values stable.

Introduce livestock in small steps

Before introducing Ring-Necked Shrimp, confirm that the aquarium is an appropriate size for the planned stocking and that ammonia and nitrite are both zero mg per litre. Temperature, pH and hardness should already be stable within the stated ranges.

Increase livestock numbers slowly. Every added animal and each increase in feeding creates more waste, while the beneficial bacteria in the filter need time to increase their processing capacity. Adding too much livestock too quickly can lead to new tank syndrome and unhealthy ammonia or nitrite.

Use three introduction checkpoints

Do not combine the shrimp’s introduction with several other livestock additions. Staggering changes makes it easier to see whether the filter is coping and whether a particular combination creates a feeding or predation problem.

Read the current delivery and Live Arrival Guarantee policy before the order is sent. Arrange to follow the current receipt and reporting process, then have the aquarium fully prepared rather than beginning setup when the animal arrives.

Make the first week measurable

• Water: continue checking for zero ammonia and zero nitrite after the increased biological load.
• Food: begin with a small wafer or shrimp pellet and allow at least 30 minutes.
• Cover: confirm that the animal can reach shelter without being displaced by another inhabitant.
• Behaviour: note increased inactivity, restlessness, unusual activity or greater hiding.
• Appearance: look for unexpected colour change, lesions, abnormal growths or exoskeleton damage.

A quiet first day is not a reason to add more livestock immediately. Keep the stocking change small, follow the established feeding schedule and let test results show whether the biological filter has adjusted.

Respond to health changes safely

Learn the shrimp’s normal pattern of activity, shelter use and feeding. Individual appearance and behaviour can vary, so a change from its usual pattern is more useful than expecting constant movement or a fixed colour.

Check the recognised warning signs

Start with measurements: ammonia, nitrite, nitrate, temperature and the recent pH pattern. Check filter operation, recent water changes, new livestock and anything newly added to the aquarium. These steps identify correctable environmental problems without exposing the shrimp to an unnecessary chemical.

Freshwater shrimp are sensitive to copper and will die after exposure even at low levels. Check every treatment label for invertebrate safety before use. Do not assume that a medicine intended for fish is safe for shrimp, and do not dose a community aquarium without considering every inhabitant.

If a health change persists or the animal shows breathing difficulty, lesions, abnormal swelling or serious exoskeleton damage, contact us with the water-test results and a clear description of the change. Keep the aquarium stable while advice is sought rather than combining several treatments or water-altering products.

• Observe: compare activity, colour and appetite with the animal’s normal pattern.
• Measure: test water and check equipment.
• Protect: use only treatments explicitly safe for invertebrates.
• Record: note when the change began and what changed beforehand.

Screen fish by mouth size and diet

Freshwater shrimp can be mixed with many aquarium species only after a careful screen. Avoid any fish able to fit the shrimp in its mouth, and avoid species known to be predatory. These two exclusions apply even when the aquarium has plants, caves or a large stated volume.

Apply the screen in order

1. Compare the fish’s mouth size with the shrimp’s 2–4 cm dispatch grade.
2. Allow for the shrimp arriving near either end of that size range.
3. Check whether the fish species is known to be predatory.
4. Consider whether the aquarium is larger than the basic shrimp-only starting point.
5. Confirm that cover and separate feeding access are present.
6. Add livestock slowly and keep testing the biological filter.

Passing the first two checks does not turn a named fish into a universal companion. Body shape, the size of the individual animals and the way they share the aquarium still affect the decision. The honest uncertainty is that a combination which passes a general screen still needs monitoring after introduction.

Remember that the animal may arrive at approximately 2 cm even though the grade extends to 4 cm. Base the mouth-size comparison on the smallest shrimp the option can supply, not only on the largest example you expect.

If fish are planned, send us the aquarium volume, water results, existing stock and proposed additions for a compatibility assessment. Include aquarium volume, measured water values, the full fish names and their approximate sizes so the screen can be applied to the actual proposed setup.

Plan each addition as a new decision

One purchase supplies one Ring-Necked Shrimp. Treat every additional animal as a new stocking decision rather than assuming that several purchases automatically create a suitable group. Add numbers slowly so the biological filter can respond to increased waste and feeding.

For a shrimp-only aquarium, start with mature filtration, stable water and multiple covered areas. Observe whether each animal can reach food and shelter. If one animal consistently loses access, adding extra food can worsen water quality without resolving the underlying stocking problem.

Work through common proposals

Do not use algae growth as the reason to increase shrimp numbers. Freshwater shrimp may graze algae, but they still require supplementary feeding, and every animal adds waste. Match the number of animals to filtration capacity and usable space, not to the amount of visible algae.

Mixed aquariums require more space than the basic figures given for groups of shrimp or snails. A larger water volume helps stability, while plants and suitable ornaments provide cover. Neither measure overrides the mouth-size and predation exclusions.

Review the combination after introduction

• Confirm that ammonia and nitrite remain at zero mg per litre.
• Watch whether the shrimp reaches food during the 30-minute feeding period.
• Look for increased hiding, restlessness, colour change or damage.
• Check whether another inhabitant controls the only covered area.
• Reduce stocking pressure rather than overfeeding when access to food fails.

Compatibility is an ongoing observation, not a one-time label. Reapply the screen when animals grow, when a new species is introduced or when the layout changes.

Answer the key buyer questions

What is Macrobrachium assamense?

It is an accepted freshwater shrimp species in the family Palaemonidae and is the animal identified here by the common name Ring-Necked Shrimp.

How many Ring-Necked Shrimp does one purchase supply?

One purchase supplies one animal of the selected option. The purchase unit is not a pair or pack.

What size is Macrobrachium assamense when dispatched?

The documented dispatch grade is 2–4 cm. Use the listed dispatch size to confirm the option attached to the order, and treat that grade as dispatch size rather than final adult size.

What aquarium should I prepare for Ring-Necked Shrimp?

Prepare a mature, filtered aquarium with gravel or sand and suitable cover. Broad guidance starts at at least 10 litres for groups of small shrimp and around 20 litres for larger shrimp, with more space when fish are included.

Should Ring-Necked Shrimp be kept alone or in a group?

Plan every animal as a separate stocking decision. Add shrimp slowly, provide covered areas and confirm that the biological filter continues to hold ammonia and nitrite at zero mg per litre.

What water values should I use?

Keep it at 17–27°C, pH 6.5–8.0 and general hardness of 4–18°dH. Ammonia and nitrite must be zero mg per litre, while nitrate should remain no more than 20 mg per litre above the tap-water level.

What should this shrimp eat?

Offer an algae wafer or commercial freshwater-shrimp pellet two or three times a week. Leave the food for at least 30 minutes, observe feeding and remove persistent leftovers before they break down.

How should I acclimate it to the aquarium?

Introduce it only after confirming mature filtration, stable water, an appropriate aquarium size and zero ammonia and nitrite. Make this a small stocking change and continue testing as the biological filter adjusts.

Which fish should be avoided?

Avoid fish able to fit the shrimp in their mouth and avoid species known to be predatory. Any combination that passes those exclusions still requires individual assessment, extra space, cover and observation.

Consult the care and identity references

• World Register of Marine Species — accepted scientific name, family and taxonomic placement.
• Wikipedia: Macrobrachium assamense — concise species identity and description history.
• OATA: freshwater shrimp and snails — broad aquarium guidance for water, space, feeding, maintenance, health and compatibility.
• RSPCA aquarium environment guidance — biological filtration and aquarium waste processing.
• Tropical Fish Co delivery and Live Arrival Guarantee policy — current dispatch and reporting terms.