Shrimp bacterial infections

The priority in the breeding of shrimps and their import is the appropriate water quality, diet and stress factor. Below we present the types of infections in aquarium shrimps that you may face up one day in the one of your shrimp tanks!

 amano shrimp

Water is important!


The most common problems and bacterial diseases arise when the tank water is organically loaded too much. Rare water changes, food remains, and residual plant debris cause a high concentration of organic matter in the water, which can lead to moult problems or even diseases. Interestingly enough, in aquariums the concentration of microorganisms is approx. 100,000 - 1,000,000 per ml, in drinking water it is approx. 10 per ml. Temperature also plays a role because microbial growth is slowed down at lower temperatures. The second point is also a proper diet, which will strengthen the immune system of the freshwater shrimp in the event of a temporary deterioration in water parameters. The third point is the stress factor. This factor may be influenced by poor water quality due to infrequent water changes.

Water parameters that can cause stress:

-too high content of nitrites, nitrates or ammonia

-temperature too high or too low

-incorrect pH or low oxygen content in the water

-the wrong selection of aquatic animals or overstocking



Shrimp are usually grown in concrete pools for Neocaridina or in large aquariums exceeding 200l for Caridina. A very important element is the recirculation system, which only reputable farms can afford. It will keep the water quality. Most importers use companies or traders from the Far East who buy from small farms offering a low price, but the quality and source are in question.

In the case of reputable farms, they are under strict veterinary control and the food is properly balanced. In the case of sources of unknown origin, the shrimps eat algae, plant debris, dead shrimps or whatever falls into the water…


The stress factor in the case of import is primarily the quality of the water in which the freshwater shrimp is kept, the second element is transport. In the case of companies / traders specializing in the shrimp farming and sale of shrimps, they order shrimps from farms, which are then transported to the headquarters, where they stay in bags for several hours. Later, check-in at the Cargo airport, the shrimps travel to Europe for another several dozen hours, further check-in at the destination airport. So, after almost 3 days, the shrimps go to the importer's shrimp tank. Shrimps are usually large - over 2 cm and are packed 100 pieces per bag. Thus, we can quickly conclude that the water is organically very heavily loaded due to the fairly large number of animals in one bag. Added to this is a long journey and pressure fluctuations. In transport, the weakened shrimp die, causing an even greater risk of infection. Therefore, an experienced importer seeks direct contact with the manufacturer. Then the delivery is possible even 42 hours from the moment the freshwater shrimp is packed. It also checks the quality through veterinary certificates of certified farms. Such manufacturers offer young shrimps that better withstand travel and acclimatization. They live from a year to one and a half longer than adult freshwater shrimps - the ones usually imported from mass shrimp production.


Bacteria, fungi, molds and other microorganisms are a natural part of any aquatic ecosystem. They are not dangerous in small amounts, but in higher amounts they can lead to infection and shrimp disease. 

red cherry shrimp


Remember that healthy gut = healthy shrimp!

Bowels have about 80% of the cells that are responsible for the immune system. The bacteria in the bowels are mostly beneficial bacteria that live in symbiosis with other microorganisms. Together, they are responsible for digesting food and the body's resistance to small amounts of pathogenic viruses. This balance is disturbed by stress or a large amount of pathogens that can displace the settled beneficial bacteria and microorganisms and lead to internal infection, necrosis.


Bacterial infections

We divide the bacteria into:

-apathogenic (harmless, useful), which to a greater extent support the functioning of the shrimp tank.

-pathogenic (harmful) bacteria that can cause infections and bacterial diseases in greater numbers.


Bacteria are found practically everywhere in the aquarium water, in the filter, in the substrate, on aquatic plants and in decorations. In the case of shrimp, all the way through the outside of the shrimp through the digestive system and into the bloodstream. These are facultative pathogens that are only just fully developing when the shrimp's immune system is weakened by deterioration in water quality, damage or transport. There are many different strains of bacteria that show up through the different symptoms of the most common bacterial diseases in shrimp: Aeromonas, Plesiomonas, Vibrio, Pseudomonas, Legionella, Campylobacter.



-high organic concentration due to neglecting water changes is caused by: food remains

or moldy food 

-weakened immune system 

-cannibalism (dead shrimp s)


Due to these factors, pathogens can accumulate even in a non infected or sick shrimp and wait for the right moment to weaken the immune system. Also, useful probiotic bacteria in the digestive system, when the shrimp's immunity decreases and they multiply to a large extent, can cause a bacterial disease. Further down the gut wall they can enter the bloodstream, causing bacterial infection. Carapace damage is also an area of attack for pathogens. They get through chitinous segments where the carapace is thin.



Unfortunately they have a wide variety. Some are invisible to the naked eye, and apart from the death of a few shrimps, it's hard to tell. Also, the presence of large amounts of freshwater shrimp near an oxygen source, e.g. a filter or under the water surface, may indicate the initial stage of bacterial disease. A popular symptom of a bacterial disease is the milky color of the shrimp's body. Other symptoms are already more visible in infected shrimp: shrimp deaths, loss of color, apathy. There may be a brown discoloration in the carapace or a discoloration of the internal organs. On the other hand for example Orange Rili Shrimp do not show lethargy and move around normally in the aquarium so diagnosis is more difficult.


We can divide bacterial infections into three following groups:

-External infection

They are mainly formed on the caudal segments, antennae, or on the back. Individuals with infected and completely damaged uropods usually have no chance of survival. Early detection of symptoms and improvement of living conditions helps to control the infection. In extreme cases, the use of Chloramphenicol treatment helps.

Symptoms: red / orange spots combined with losses of uropods and antennas. Recognition can be confused with brown spot disease (rust disease).


-Internal infection

Much more dangerous because they are unpredictable and attack the whole shrimp's body. Dead shrimps can be a potential source of infection in healthy individuals that's why internal bacterial infection is probably the most dengerous one among these three types.

Symptoms: It varies greatly depending on the individual. Starting with the orange-red color of the abdomen, it can cover the entire body within a few hours. Sudden single or massive incidence animals associated with local discoloration (or lack thereof) of the abdomen. Death usually takes a few days. When the entire population is infected, single individuals usually die at intervals of 1-2 days over a period of weeks. In the case of internal infections, the cause may be several bacterial strains attacking various internal organs simultaneously.


-Organ infection

In many transparent shrimp species where the internal organs are clearly visible, internal infections within them can sometimes be observed. In healthy shrimp, they are usually dark (gray, greenish, brown), while in sick shrimps they may be pink in color. Research has shown that micrococcus (bacteria) are responsible for this. Infected animals die after 2-4 days. So far, no treatment has been found. However, you should isolate sick or dead individuals as soon as possible because there is a high risk of infection the rest of the shrimp aquaculture.

Symptoms: Pink colouration of internal organs in "glassy" shrimp species.

So how to treat bacterial infections in freshwater shrimp?

Fist of all, on the market there are different solutions to treat shrimp diseases. To use them, it's worth creating a hospital tank where we can do the healing bath. Remember that such a quarantine tank shoudn't have activated carbon in the substrate because it can absorb the substances that have positive influence on shrimp diseases. Moreover we wouldn't rather recommend the salt bath in case of shrimps although the aquarium salt can affect beneficially on many other aquatic organisms. Although this topic is controversial, many fish having regular salt baths in a quarantine tank (not the general one!) get back to health. The second option is shrimp foods dedicated to infected shrimps. Such food contains mainly ingriediends strenthening the immune system such as beta glucan or spirulina. This food can be used on everyday basis for prophilaxy or disease control. Depending on the brand and form, the way of feeding is different so always follow the menufacturer's recommendations.

Recognision is not easy

Many readers may think- if this is a bacterial infection, why not to give the infected shrimp the antibiotics? The answer is easy. Antibiothics have healing properties only in case of bacterial diseases. Unfortunately we can't be 100% sure that we have to deal with bacterial infections, not a fungal infection. Certainity can be only proven under the microscope. Fungal infection is often connected with feeding. Fungal spores attack the gut and if the immune system is weakened, the shrimp can die. For example a black spot disease / brown spot disease / rust disease can be qualified to both categories- bacterial infections and fungal infections becuase the symptoms can be caused by fungi (e.g. Ramularia astaci, Cephalosporium leptodactyli and Didymaria cambari) and/ or gram negative bacteria (Aeromonas, Pseudomonas and Citrobacter, etc.). Viral diseases are dengerous for shrimps as well as fungal diseases and bacterial diseases. For example, white spot syndrome virus is on of the most lethal shrimp and infectious diseases.

To sum up, shrimps are sensitive creatures. While buying them, be sure that they come from a reliable farm and the transit is not too long. If you see the difference in your shrimp appearance or behavior, be aware that it may be a bacterial infection. Proper identification in proper time can save your shrimp life. Always remember to isolate infected or dead individuals from healthy ones in order to avoid further infection of the rest.