Caridina serratirostris (also known as Ninja shrimp) is one of the most colorful and unique shrimp species in the aquarium hobby. These little freshwater shrimp have developed an ability to rapidly change their color to match the environment and avoid predation through camouflage.
Generally, Ninja shrimp are no different to care for than any other freshwater dwarf shrimp species and can be recommended even for beginners. They are gorgeous, and, at the same time, low-maintenance pets.
The only problems though are that they are very rare on the pet trade market and require brackish water to breed.
Unfortunately, the ecology of Caridina serratirostris is poorly researched and much is still unknown about these shrimp. As a result, there is a lot of conflicting or sometimes even totally false information on the Internet.
This profile guide will give a special look into this remarkable species. In this article, I gathered everything that is currently known about Ninja shrimp including their behavior, feeding preferences, ideal tank setups, and how to care for them.
Quick Notes about Ninja Shrimp
||Chameleon shrimp, Christmas shrimp, and Honey shrimp|
|Scientific Name||Caridina serratirostris|
|Tank size (minimum)||10 gallons (~40 liters)|
|Size||up to 2.5 cm (1 inch)|
|Optimal Temperature||24 – 27°C (~75°F – 80°F)|
|Optimal PH||6.5 – 8.0|
|Optimal GH||2 – 14|
|Optimal KH||1 – 8|
|Optimal TDS||100 – 300|
|Nitrate||Less than 20 ppm|
|Life span||up to 1.5 years|
|Color Form||Yellow, orange, red, black, brown, cream, etc.|
Taxonomy problems of Ninja Shrimp
There is considerable confusion surrounding the taxonomy of many species of Caridina. There are probably several species that are still included in what is now called Caridina serratirostris.
The differences can be so small that is required a microscope to see them. For example, in 2006 scientists separated Caridina serratirostris and Caridina celebensis on the basis of whether there was a tiny arthrobranch present at the base of the third maxilliped.
Thus, it is not surprising that some sellers can accidentally sell this species under other names.
Origins, Natural Habitat of Ninja Shrimp
Caridina serratirostris is widely distributed in the Indo-Pacific. This species having been recorded in literature from Madagascar, Seychelles, Mauritius, Comores Is., Okinawa, S.E. Asia, N.E. Australia, New Caledonia, Fiji (Fiji Islands), Tahiti, and the Marquesas in French Polynesia.
These shrimp are mostly found close to the sea, in lower reaches of rivers or streams on islands. Thus, being freshwater shrimp, Ninja shrimp can also live in slightly brackish water.
In their natural habitat, they prefer leaf litters and riverbank vegetation, and are often found hiding under rocks.
Note: As pets, Ninja shrimp are pretty common in Japan, but are very rare in North America or Europe.
Why are They Called Ninja Shrimp?
Ninja shrimp live up to their name because of their ability to change colors really fast, so it seems like the “original shrimp” vanish into the surroundings… like a ninja.
According to some studies, the color markings (or chromatophores) in their skin, expand or contract to accomplish this feat.
Description of Ninja Shrimp
Caridina serratirostris are quite small shrimp. Males usually do not grow larger than 2 cm (0.6 inches) whereas females can reach 2.5 cm (1 inch) in length.
This is a very colorful shrimp species. They come in many color variations like yellow, orange, red, black, brown, cream, etc. There are many pattern variations as well, they can be with or without white stripes on the back or numerous small stripes across the body.
Once a proper aquarium is set up and optimum living conditions are met, Ninja shrimp can live up to 1.5 years in captivity.
The Behavior of Ninja Shrimp
As I have already mentioned, Ninja shrimp can change color incredibly fast to blend into the surrounding. They can also do that depending on their mood or when they are experiencing stress from their environment.
Despite their belligerent name, Ninja shrimp are actually very peaceful animals. They are completely harmless and will not bother anybody in the tank. It makes this species a great choice for a peaceful community tank.
Ninja shrimp are very shy; they will spend most of their time hiding in the plants or under the driftwood. So, they need to be kept in large groups. The bigger their colony, the safer they feel and more confident they act.
They are nocturnal. The pick of their activity starts at dusk and gradually stops before sunrise. This nocturnal behavior is mainly associated with attempting to avoid visual predators whilst feeding.
Interesting fact: On a 24-h cycle, dusk is a period in which algae had maximum nutrients at the end of the photosynthetic period corresponding to profitable conditions for grazers to feed at the end of the light period.
- Social: Yes
- Active: At night
- Peaceful: Yes
Feeding Ninja Shrimp
Feeding them is very easy and straightforward. Like most dwarf shrimp. Ninja shrimp are scavengers and omnivores. As such these shrimp can feed on dead animal and plant matter as well as commercial (fish, shrimp, crab, etc.) food.
In an aquarium, Ninja shrimp will be your clean up crew against algae, biofilm, debris, and waste.
Nonetheless, in order to keep them healthy and happy or if you want to enhance their coloration, I would definitely recommend supplementing their diets with vegetables and commercial foods such as (links to Amazon):
Providing them with dry leaves and blanched vegetables (like carrots, sprouts, spinach, cucumber, zucchini, etc.) will also help them to get all the necessary microelements necessary for molting.
Like all crustaceans, Ninja shrimp have a multi-layered exoskeleton hardened by calcium salts except around the joints where the integument is soft and flexible.
Therefore, it is absolutely important to make sure that they get enough calcium (for the exoskeleton). We can do that by regularly feeding specialized invert foods or calcium-rich vegetables.
|Calcium plays a huge role in any shrimp. Therefore. I highly recommend reading my article “How to Supplement Shrimp and Snails with Calcium”.|
How Often to Feed Ninja Shrimp?
If you have a matured tank (with algae and biofilm), you can feed them once in 2 – 3 days. It will make the shrimp keeping process both inexpensive and highly convenient.
Remember it is better to underfeed than overfeed!
You can read more about it in my articles:
- How and What to Feed your Shrimp
- How Often and How Much to Feed Shrimp
- Indian Almond Leaves and Alder Cones in a Shrimp Tank
- How to Blanch Сucumbers and Zucchini for Shrimp, Snails and Fish the Right Way.
Ninja Shrimp and Live Plants
Ninja shrimp do not eat healthy plants and can, therefore, be kept in beautifully planted tanks. Even more, you will benefit from them!
As scavengers, they will clean your tank by eating dying, rotting, or decaying plants.
Note: Keep in mind that hobbyists often confuse grazing on (eating algae) with eating the plant.
Caring and Keeping Ninja Shrimp
Caridina serratirostris is a pretty hardy species and can withstand varied ranges of water parameters.
Nonetheless, if you want them to thrive, you still need to address their core needs! Here are some care guidelines to help you out.
First of all, it is important that you cycle your tank before bringing shrimp home. Once the tank is cycled you need to check the quality of the water using a test kit.
Ninja shrimp do not require a lot of space, however, it will not be a good idea to keep them in small tanks. Especially, you do not have experience in shrimp keeping.
It is all about water parameters and stability.
The point is that more water volume will increase the stability of water parameters which is very important when caring for dwarf shrimp. In small tanks, it can be difficult to be in constant control over your water parameters where everything can go wrong very fast.
Therefore, in my opinion, it is better to keep them in a tank of at least 10-gallons (40 liters). It will easily accommodate at least 40 – 50 shrimp.
Temperature: Although Ninja shrimp can live in a wide range of temperature conditions 20 – 30°C (68 – 86°F), they prefer fairly warm water. So, the optimal temperature in the aquarium should be in the range of 24 – 27°C (75 – 80°F).
pH: Optimal water pH should be provided for this species in the range of 6.5 – 8.0.
Hardness: They will appreciate optimal KH 1 – 8 and between 2 – 14 GH.
Ninja shrimp need only freshwater. They use brackish water only for reproduction purposes when they are releasing eggs.
Although these shrimp are pretty hardy and can be kept even in the tap water (like Neocaridina shrimp), for the best result, I’d always recommend using RO/DI water remineralized with Salty Shrimp GH/KH+.
This way you can control your water parameters and create the optimal conditions for them.
If you still decide to keep them in tap water, you need to remember that it should be free from chlorine and chloramine, as these things are toxic to them. Let it age for 24 hours before using it.
You can also use a water conditioner (like Seachem Prime or similar) to bind heavy metals, ammonia, nitrites, or nitrates present for up to 48 hours.
Ninja shrimp are nocturnal. Basically, they do not really depend on the light. Therefore, lighting should be adapted to the needs of plants in the tank.
For more information, you can read my “Advanced Guide to Planted Tank Lighting”.
Ninja shrimp can be kept in any tank with any type of substrate (soil, sand, or gravel).
There are no special requirements as well. As long as you have got the filter that works great with the size of the tank you have got you will be fine.
Personally, I would always recommend using sponge filters or matten filters for any small tank setups.
These filters are cheap, easy to maintain, and clean; they provide a lot of surfaces to graze on.
In aquariums, decorations play an important role for the Ninja shrimp – they provide hiding places (shelter and protection) and minimize stress to your shrimp.
This is also crucial for the molting process (read more here about it)!
If they are going to be in a community tank, there should be plenty of dark areas for them to hide in and these should be created out of rocks, driftwood, PVC pipe, plastic tunnels, plants, etc.
Important: Before putting Ninja shrimp into your tank do not forget to carefully acclimate them for a few hours. Do not rush! Do it very slowly to prevent any unnecessary stress.
Be careful with chemicals like copper (read more). Like all crustaceans, Ninja shrimp do not tolerate copper-based medications.
Basic Tank Equipment (links to check the price on Amazon)
Breeding Ninja Shrimp
Unfortunately, it is extremely hard to breed Ninja shrimp in captivity. So far, there have been no reports of successful breeding Caridina serratirostris in home aquariums.
Currently, the pet industry completely depends on wild-caught species.
According to the study, adults of this species inhabit and reproduce in freshwater environments, but their larvae require saline water for successful development.
When the eggs develop into larvae, females release them to drift to the sea, where the larvae undergo metamorphosis through several molts. After that, the juveniles migrate back to the parental freshwater habitats.
The scarce information in scientific literature tells us that:
- Caridina serratirostris requires brackish conditions to hatch. Salinity concentration should be 17 – 25 ppt. The ideal temperature for breeding ranges from 25 – 27°C (77 – 80°F).
Note: Suitable rearing conditions can vary because adults of these species have slightly different geographical distributions.
- Ninja shrimp have very small eggs (around 0.33 to 0.37 mm along the larger diameter. It allows them to produce hundreds of larvae.
- After hatching, larvae require a special diet, for example, Tetraselmis and cultured zooplankton rotifers.
- According to some reports, larvae molt to the juvenile stage 34–46 days after hatching. The mean survival rate is around 53%.
- In one of the experiments, under laboratory conditions, larvae died on the 14th day while being trapped by the surface tension of the rearing water during the molting The reason why this species is vulnerable to the surface tension of water remains unknown. Some scientists suppose that it can be a specific phenomenon in shallow water in small rearing containers. Therefore, to avoid these incidents in the future it was recommended to breed Caridina serratirostris in relatively large containers with deeper water.
Ninja Shrimp and Suitable Tankmates
The ideal situation for the Ninja shrimp is a species tank, but they can be kept with other fish as long as those species are chosen with care. Large and/or aggressive fishes should be avoided.
Ninja shrimp are compatible with:
- Shrimp (Cherry shrimp, Snowball shrimp, Caridina cf. Babaulti, Ghost shrimp, Amano shrimp, Blue tiger shrimp, Blue Velvet Shrimp, Blue Bolt shrimp, Vampire shrimp, Crystal shrimp, Bamboo shrimp, Cardinal Shrimp, Red Nose shrimp, etc.
- Freshwater snails (for example, Japanese trapdoor snails, Ramshorn snails, Nerite snails, Malaysian Trumpet snails, Chopstick snails, Black Devil Snails, Asolene spixi, Rabbit Snails, White Wizard Snails, etc.).
- Small and peaceful fish (for example, Pygmy Cory Catfish, Otocinclus Catfish).
Keep Ninja shrimp away from all types of crayfish and most types of freshwater crabs. Even small African Dwarf Frogs can and will try to catch the shrimp whenever it is possible.
Ninja shrimp is most notable for its incredible color-changing ability. They are really unique animals and can decorate any home aquarium.
Similar to the Neocaridina shrimp, they are much harder than most Caridina species and can tolerate a wide range of water parameters.
Unfortunately, Ninja shrimp are a pretty rare find on the pet market.
- Larval Rearing of Three Amphidromous Shrimp Species (Atyidae) under Different Feeding and Salinity Aquacultuye Science. 53(3), 3
- Dietary effects of phytoplankton and zooplankton on larval survival, duration and growth of four Caridina species (Decapoda: Caridea: Atyidae) under laboratory conditions. Crustacean Research. 2020. Vol.49: 225–236
- The Atyid shrimps of Fiji with description of a new species. S. C. Choy. Zool. Med. Leiden 65 (27), 24.xii.1991.
- Freshwater shrimps of the family atyidae (crustacea: decapoda: caridea) from peninsular Malaysia and Singapore. The Raffles Bulletin of Zoology 2007 55(2): 277–309.
- Ninja Shrimp (Caridina serratirostris). Ecological Risk Screening Summary. U.S. Fish & Wildlife Service, August 2017.
- Diversity of freshwater shrimp (decapoda) from bandealit rivers merubetiri national park, East Java, Indonesia. V E Susilo et al 2020.
- Report on a collection of freshwater shrimps (Crustacea: Decapoda: Caridea) from the Philippines, with descriptions of four new species. The Raffles Bulletin of Zoology54(2):245-270. 2006