Red Rili Shrimp (Neocaridina davidi)

Red Rili Shrimp in brief

Red Rili Shrimp are a selectively bred colour form of Neocaridina davidi, the freshwater dwarf shrimp better known as the cherry shrimp. The World Register of Marine Species lists Neocaridina davidi (Bouvier, 1904) as an accepted species in the family Atyidae. Older sources and some trade labels use the names Neocaridina heteropoda or N. denticulata sinensis; this listing uses the accepted name.

Wild shrimp of this species are a mottled brown. According to the Wikipedia species summary, they come from Taiwan, eastern China, the Korean Peninsula and Vietnam, where they live in lakes, ponds, rivers and streams, and selective breeding has produced red, orange, yellow, green, blue, violet, white and clear forms. The popularity of the red form is where the name cherry shrimp comes from. Adults are approximately 3–4 cm long at maturity.

They are peaceful, busy grazers that spend their day picking over plants, wood and substrate. The most important condition for success is a mature, filtered freshwater aquarium with zero ammonia and nitrite, plenty of cover and no fish large enough to eat them.

Choosing your shrimp

Each purchase supplies one live Red Rili Shrimp in the size you choose: 1–1.5 cm or 2–2.5 cm. The size you select is the size supplied, not the adult size. Both are the same Red Rili Shrimp; only the size on arrival differs. The 2–2.5 cm shrimp are closer to adult length and easier to spot among plants, while the 1–1.5 cm shrimp still have some growing to do.

Shrimp species are usually social, and the OATA care sheet for freshwater shrimp and snails advises keeping them in groups of at least five, so set the quantity to five or more rather than buying a single shrimp. A group also makes the colour show far better in a planted tank than one or two animals ever will.

Sex is guaranteed only when the selected option explicitly states male or female. This Red Rili Shrimp listing has no sex-guaranteed option. Every photo in the gallery shows shrimp carrying a cluster of yellow eggs. The shrimp you receive are chosen by size, not by sex or breeding condition, so they may not be carrying eggs and a group cannot be promised to contain both sexes.

The red-and-clear pattern

The Red Rili pattern is easy to recognise in the gallery: a solid red head and tail with a clear, glassy section through the middle of the body. The amount of red and the sharpness of the clear band vary from shrimp to shrimp, which is part of the appeal of a group. Gallery images have been digitally enhanced to improve image quality. Natural colour, pattern, size and maturity can vary between live animals.

Because Red Rili, cherry red, blue and other lines all belong to one species, their basic care is the same. What differs is inherited colour. If you want to keep one colour line looking consistent over generations, give it a tank of its own rather than mixing lines, because mixed colours may not breed true. You can compare the other colour forms in our cherry shrimp range.

Decide what success looks like

It helps to decide what you want from the shrimp before choosing how many to buy. A display group in a planted community tank, a single-colour line you hope will breed true and a nursery aimed at raising as many young as possible each need different decisions about fish, space and a spare tank.

• Write down your measured water values, not a guess based on where you live.
• List every animal that will share the tank, including any you plan to add later.
• Decide whether you have somewhere to move shrimp if a tank mate starts hunting them.

That short record takes very little time and makes later troubleshooting far easier than changing several things at once.

Planning the aquarium

Tank size without a shrimp-per-litre rule

OATA recommends an aquarium of at least 10 litres for a group of small freshwater shrimp and says it needs to be larger if fish share it. It also makes the point that a larger aquarium keeps temperature and water quality more stable. We use a mature, filtered 20-litre aquarium as a more cautious starting policy for a small group, because the extra water gives more headroom for feeding mistakes, equipment and summer heat. Neither figure is a biological minimum or a formula for how many shrimp a tank can hold.

Plan in this order instead:

1. Confirm the filter is biologically mature and that ammonia and nitrite read zero.
2. Work from the real water volume and footprint once substrate, wood and equipment are in.
3. Set aside covered areas where the starting group can graze and feed.
4. Count every adult tank mate, plus the possibility that young shrimp survive and the group grows.
5. Leave headroom for feeding errors, maintenance and warm weather.

Filter and intakes

A filter is always essential. The RSPCA explains that animals release toxic ammonia and that a working biological filter holds the bacteria that turn it into nitrite, also toxic, and then into the safer nitrate. For shrimp, choose a filter whose intake can take a fine guard or a suitable sponge: newly hatched shrimp are small enough to be drawn into an open intake.

Substrate, plants and cover

OATA suggests aquarium gravel or sand and, ideally, live plants to provide cover. Where live plants are not used, plastic plants and ornaments such as plant pots or model caves give shelter instead. Add aquarium-safe wood, rock or dense planting so that sheltered surfaces are available all around the tank, and keep enough open access to reach equipment for cleaning. Our guide to setting up a first shrimp tank walks through the equipment in more detail.

A first shrimp tank, step by step

1. Place the tank somewhere out of direct sun, on a level surface that can take its full weight.
2. Add rinsed substrate, then wood, rock and plants, leaving room to reach the filter and heater.
3. Fill with water treated with tap water conditioner, the same treatment OATA asks for with replacement water.
4. Run the filter and let the aquarium mature, testing as it goes, until ammonia and nitrite stay at zero.
5. Fit the intake guard and lid, and check the temperature over several days.
6. Only then add the shrimp, and add any other animals slowly afterwards.

Lid and ventilation

A lid or secure cover helps prevent shrimp climbing out, but it must not block ventilation or trap cables. Check the gaps around filter pipes and heater cables as part of the set-up.

Why the tank must be mature

Mature is a biological state, not a fixed wait of a set number of weeks. The filter must be able to process the waste the shrimp and any other animals will produce, and tests must show that ammonia and nitrite stay at zero. OATA's freshwater aquarium set-up guidance covers cycling, regular testing and adding animals gradually, and its shrimp sheet asks you to check that ammonia and nitrite are zero before any shrimp go in.

Add livestock slowly. The beneficial bacteria in a filter grow to match the load they receive, so every new group of animals and every increase in feeding needs time for the bacteria to catch up. Overstocking or stocking too quickly causes what OATA calls new tank syndrome: ammonia and nitrite rise and shrimp can become ill or die.

Signs the tank is ready

• Ammonia and nitrite read zero on repeated tests, not just once.
• Nitrate sits no more than 20 mg per litre above your tap water level.
• Temperature holds steady through the day and night.
• Plants, wood or rock have been in long enough to carry a visible film.
• The filter intake is guarded and the lid fits.

Biofilm matters

Established surfaces carry biofilm, the thin living film that shrimp graze constantly. In controlled culture work, biofilm on suitable substrates improved juvenile survival and growth and helped maturation and egg incubation. That is a good reason to add shrimp to a settled aquarium with plenty of surface area. It does not make an old-looking tank safe on appearance alone, and biofilm by itself is not a complete feeding plan.

Water values and UK tap water

OATA describes freshwater shrimp and snails as usually undemanding of water chemistry and gives these values as a general guide for the whole group. They are planning figures for the whole group rather than measured limits for Neocaridina davidi.

What research adds

Temperature changes how these shrimp grow and breed. In controlled culture at 24°C, 28°C and 32°C, temperature altered growth and reproduction, and in one high-temperature experiment females spawned at 28°C but not at 33°C. Those were experimental conditions. They explain why stability matters; 33°C is not a care target, and none of the figures replaces measuring your own tank.

Your tap water

UK tap water is not one chemistry. Hardness varies with geology and supply, and your water company can give you local figures. Test the aquarium as well, because rock, substrate, top-ups and treatments all change it. Water from an ion-exchange softener has had its calcium and magnesium replaced with sodium, so softened does not automatically mean suitable for shrimp. Our guide to aquarium water chemistry explains each test, and the water parameter matcher lets you compare your readings with stated guidance.

Heating in a UK home

Whether you need a heater depends on your room, not on the season or your postcode. Measure the room and aquarium temperatures over several days. If they cannot stay within a stable range inside OATA's 17–27°C group guidance, fit a correctly sized, guarded heater with a thermostat. Guarding matters because shrimp climb over equipment.

Warm rooms need the opposite plan. A tank in a sunny window or a hot loft can climb well above the range in summer, and the experimental work above shows that high temperatures affect breeding. Keep the tank out of direct sun, allow airflow over the surface and watch the thermometer on hot days.

Feeding and grazing

What they eat

These shrimp are omnivores. OATA's sheet describes freshwater shrimp as grazers that work over algae in the aquarium and says this should be supplemented with algae wafers, or with commercial pellets made for freshwater shrimp, so they get enough food. Our own guidance is to use an appropriate complete sinking shrimp food as the nutritional base and let grazing on biofilm and soft growth fill the gaps.

How often and how much

OATA suggests feeding freshwater shrimp only two or three times a week. Leave pellets or wafers for at least 30 minutes so the shrimp have time to find them, and take care not to overfeed: uneaten food breaks down and releases toxic waste into the water. Treat that rhythm as a starting point, then adjust by what you see:

• Can every shrimp reach the food without being pushed away?
• Is food regularly left to decay?
• Is there algae or biofilm to graze between feeds?
• Has the group grown, shrunk or started producing young?
• Do your test results change after feeding?

Remove what is left over and adjust the next portion rather than adding more.

Colour and food

Pale colour is not automatically a food problem. Lineage, lighting, substrate, stress, health and even camera settings all affect how red a shrimp looks, so check water and conditions before changing the diet. Grazing shrimp also do not remove fish waste or guarantee control of any particular algae; they tidy surfaces, not the underlying causes.

Weekly routine

• Change 25% of the water at least once every week, as OATA strongly recommends, using a siphon to lift solid waste from the gravel.
• Treat all replacement water with tap water conditioner to remove chlorine or chloramine before it goes into the aquarium.
• Test the water regularly, at least once a week, so that ammonia and nitrite cannot build up unnoticed.
• Check the filter for blockages. When it needs cleaning, do not run it under the tap; rinse it lightly in the tank water you removed during the water change so that the beneficial bacteria survive.
• Look over the intake guard, heater guard and lid while your hands are in the tank.
• Count the shrimp you can see and note anything unusual, so changes stand out quickly.

If a test shows ammonia or nitrite

Any reading above zero means the filter is not keeping up. Stop adding food for the moment, carry out a partial water change with conditioned water at the same temperature, and check the filter for blockages. Think back over what has changed: new animals, heavier feeding or recent cleaning can all push a filter past what its bacteria can handle. Keep testing until both readings are back at zero before adding anything new.

OATA calls good husbandry essential for freshwater shrimp. Small, regular jobs done every week keep the water steady, and steady water is what these shrimp need most.

Moulting and health

What normal looks like

Healthy shrimp spend most of their time picking at surfaces with their front legs, moving steadily over plants, wood and substrate. They come out to food quickly, keep their legs and antennae moving and hold their colour from day to day. Knowing what your group looks like on an ordinary day is the easiest way to notice when something changes.

Moulting

Shrimp grow by shedding their exoskeleton, and an empty moult lying on the substrate can look alarmingly like a dead shrimp. Count the group before you worry. Hiding often accompanies moulting too, but neither a shed shell nor hiding on its own tells you that anything is wrong.

Changes to watch for

OATA lists signs worth noticing in freshwater shrimp:

• Behaviour: more inactivity than usual, restlessness or unusual swimming.
• Colour: darker or paler than normal.
• Temperament: more hiding or more aggression than normal.
• Breathing: changes in rate or effort, or more time spent where oxygen is higher.
• Appearance: white spots, discolouration, lesions, abnormal growths, damaged exoskeleton or lost limbs.
• Condition: noticeable weight gain or loss, or abnormal swelling.
• Feeding: less interest in food.

What to do

1. Measure temperature, ammonia and nitrite straight away, then review nitrate, pH and hardness.
2. Check filtration, aeration, heating and any recent maintenance.
3. Think about anything new: animals, plants, decor, sprays used near the tank, food or treatments.
4. Compare the affected shrimp with the rest of the group.
5. Take clear photographs, and seek suitably qualified aquatic or veterinary help if signs persist or are severe.

A 2023 survey found small organisms living on the shells of some commercially sourced N. davidi, with prevalence varying by source. That is a reason for careful inspection and good biosecurity, not for medicating automatically whenever a white mark appears.

Copper and medicines

OATA warns that shrimp and snails are very sensitive to copper and will die if exposed even to low levels. Make sure every treatment added to the aquarium is safe for invertebrates, read the full label including any invertebrate warnings, and identify the problem before treating anything.

Arrival and first days

We hand-pack every order. Shrimp are hand-bagged in pure oxygen and packed in an insulated poly box, with a heat pack when the weather calls for it, and a licensed live-animal courier delivers the parcel. We email the tracking number and your confirmed delivery date so you know when to be in. If you would like to compare water chemistry before the shrimp arrive, ask us for the values they are held in.

1. Be at the delivery address: live animals cannot be left unattended, and the Live Arrival Guarantee requires someone to receive the parcel.
2. Before opening, start one continuous video showing the parcel still sealed with the outer box visible, then you opening it, then the shrimp still inside the sealed bag. This video is needed for any Live Arrival Guarantee claim.
3. Open and inspect the parcel the same day it arrives.
4. Float the sealed bag in the aquarium for 20–30 minutes before releasing, so the temperatures come together slowly.
5. Release the shrimp without pouring the bag water into your tank.
6. If anything has gone wrong, contact us the same day, with WhatsApp the fastest route, including your order number and the video, and we will arrange a replacement or refund.

The full terms are on our delivery and Live Arrival Guarantee page.

Biosecurity

Keep a net and bucket for this tank where you can, and watch new arrivals closely for the first days. Never release shrimp, aquarium water, plants or the contents of equipment into the wild or into a drain that can reach it. The species tolerates a wide range of conditions and has become invasive in thermally polluted waterways in Japan, the United States, Poland and Germany, where released captive shrimp are thought to be the source. If you ever need to rehome shrimp, follow the GB Non-native Species Secretariat's pet code.

Eggs and young

Cherry shrimp are not livebearers. A mature female carries her eggs beneath her abdomen, and the young hatch as tiny bottom-dwelling shrimp. There is no distinct larval stage and no need for the salty water that Amano shrimp larvae require, so the whole cycle can take place in a freshwater aquarium.

That still does not guarantee a colony. Young shrimp survive best with mature surfaces to graze, suitable food, protected filter intakes and dense cover such as moss, and they are at their most vulnerable to fish. We cannot promise a sex mix from an unsexed purchase, a maturity age, an egg count, an incubation period or a growth rate, because each depends on the batch and the conditions in your tank.

If you want one colour line to stay consistent, keep it in a tank of its own. Red Rili kept alongside other colour forms of the same species can interbreed, and their offspring may not look like either parent.

Fish and shrimp together

OATA describes freshwater shrimp as generally compatible with most species, with two firm exceptions: they should not be mixed with any fish that can fit them in its mouth, or with any species known to be predatory. Its sheet also notes that shrimp may be eaten by common aquarium fish, which is why each pairing needs thought.

No fish is guaranteed safe with adult shrimp, and a fish that ignores adults may still hunt newly hatched young. Before adding any fish, check:

• its adult mouth size, hunting habits and territorial behaviour;
• how fast it feeds, and whether shrimp will still reach food;
• whether its temperature and water needs overlap with the shrimp's;
• whether there is cover the shrimp can still use after plants are trimmed;
• the extra risk to a shrimp straight after moulting;
• whether you want display coexistence or the best survival of young;
• where you would move the shrimp if behaviour changes.

Making a community work

If you do keep shrimp with fish, give them the advantage. Dense cover such as moss and fine-leaved plants gives adults and young somewhere to retreat, and it needs to stay dense after every trim. Feed in a way that lets food reach the substrate, so shrimp are not left waiting while fish eat everything in mid-water. Watch the first days after each new fish closely, and have a spare tank or container ready so you can separate the shrimp if a tank mate starts hunting them.

A shrimp-only aquarium

Keeping shrimp on their own removes fish predation, which gives young shrimp their best chance. It does not remove the other risks: crowding, equipment, feeding and water quality still need the same care. Our full Cherry Shrimp care guide compares these choices in more depth.

Snails and other shrimp

OATA covers freshwater shrimp and snails on the same care sheet, with the same water guidance, and describes both as generally compatible with most species. One exception is worth knowing: the assassin snail preys on other snails, so it matters in a tank where you also keep snails.

Other colour forms of Neocaridina davidi share this species' care, but they can interbreed with Red Rili. That is fine in a mixed display; it is not what you want if you are keeping one colour line for its looks.

Questions keepers ask

How big do Red Rili Shrimp get?

Adults of the species are approximately 3–4 cm long at maturity, and OATA puts small aquarium shrimp at about 3 cm. Plan cover, food and tank space around that adult size.

What size aquarium do Red Rili Shrimp need?

OATA recommends at least 10 litres for a group of small freshwater shrimp, and more if fish share the tank. We use a mature, filtered 20-litre aquarium as a cautious starting point; neither figure is a shrimp-per-litre formula.

How many Red Rili Shrimp should I keep together?

Keep a group. OATA notes that shrimp species are usually social and should be kept in groups of at least five, so start with five or more.

Is Neocaridina davidi suitable for beginners?

It can suit a careful beginner, but only in a mature, filtered aquarium where ammonia and nitrite already read zero and water testing is routine. Hardy never means suitable for a new or overheating tank.

What do Red Rili Shrimp eat?

They are omnivorous grazers that pick algae and biofilm from surfaces. Add algae wafers or a complete shrimp food; OATA suggests feeding only two or three times a week, leaving food for at least 30 minutes and then removing what is left.

What temperature and pH do they need?

OATA's broad guidance for freshwater shrimp is 17–27°C, pH 6.5–8.0 and general hardness 4–18 dGH, with ammonia and nitrite at zero. Choose steady values inside that range and change them slowly.

Are Red Rili Shrimp aggressive, or will they nip fins?

No. They are peaceful grazers that do not chase or nip fish. The risk runs the other way: OATA notes that shrimp may be eaten by common aquarium fish, and newly hatched young are the most vulnerable.

What can Red Rili Shrimp live with?

OATA says freshwater shrimp are generally compatible with most species but should not be mixed with fish that can fit them in their mouths or with predatory species. No fish is guaranteed safe for newly hatched young, so a shrimp-only tank protects them best.

How do Red Rili Shrimp arrive alive in the UK?

We hand-bag them in pure oxygen inside an insulated poly box, with a heat pack when the weather calls for it, and a licensed live-animal courier delivers them. Be at home, film a continuous unboxing video before opening, then float the sealed bag for 20–30 minutes before releasing.

References

• World Register of Marine Species: Neocaridina davidi, for the accepted name and family.
• Wikipedia: Neocaridina davidi, for the native range, colour forms, adult length, development and introduced populations.
• OATA: How to look after freshwater shrimp and snails, for the group water values, aquarium size, group size, feeding, maintenance, health signs and compatibility.
• OATA: How to set up and look after a freshwater tank or aquarium, for cycling, testing and gradual stocking.
• RSPCA: fish environment, for filtration and the nitrogen cycle.
• Tropical Fish Co Cherry Shrimp care guide, linked in the compatibility section, for our 20-litre starting policy, temperature research, tap water, moulting, health and breeding notes.
• Tropical Fish Co delivery and Live Arrival Guarantee terms, linked in the arrival steps.