HealingCanh Shrimp

Explaining Shrimp Swim Behavior

If we want to keep our shrimp healthy and happy, we need to understand what they are saying with their behavior. For example, what does it mean, when they start swimming around frantically in the tank?

In fact, it is not uncommon for shrimp to swim erratically. They do it all the time during mating. At the same time, jerky movements and straining can be a sign of stress which can include water quality problems, predators, disease, acclimatization, etc.

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Let's take a closer look at the main reasons why shrimp keep swimming around and what you need to do in an emergency.

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Mating of shrimp

In shrimp, mating and reproduction are closely related to the molting cycle.

Briefly, adult females have eggs in the ovary, located at the junction of the cephalothorax (carriage) and with the tail (belly). So when eggs are released from the ovaries, they travel to the fallopian tubes for fertilization.

However, in order to transfer eggs from the ovary, the shrimp must molt. It makes the cuticle of the newly molted female soft and flexible, making fertilization possible.

At the same time, the newly molted female begins to release some pheromones into the water. It is a signal to the males that it is ready to mate.

These signaling chemicals have an overwhelming effect on males. They couldn't resist it and as a result the male shrimp started swimming around the tank like crazy. They want to find that female and mate.

Mating only lasts a few seconds, but the pheromone stays in the water for an hour or even longer. Once the pheromone lapses, the erratic swimming behavior stops immediately.

Shrimp need hiding places to be happy. It is important to minimize stress for the shrimp by giving them plenty of places to hide.

The problem is that for females, the molting (mating) process can become really dangerous if they are exposed and chased by multiple males.

Remember that after changing the shells, they are soft and weak. So the males can easily stress or even harm them in this frenzied state.

Tension in shrimp

Now, let's talk about the negative side of swimming around behavior in the shrimp tank.

Despite its small size and fairly simple nervous system, dwarf shrimp can become stressed just like all other animals.

Shrimps often become stressed in response to: inappropriate environmental quality, (bad water parameters), improper adaptations, large water changes, toxins, parasites or disease, unhealthy tank mates Compatible.

Is swimming around behavior the only sign of stressed shrimp?

No it is not. There are several signs of a stressed shrimp.

It can: lethargy, loss of appetite, loss of color, molting problems, reduced growth, decreased success of fertilization, loss of eggs, decreased fertility, erratic swimming (it's just one). in the signs).

Unsuitable water quality

Bad water quality is probably the main reason why shrimp can swim like crazy in the tank. Inappropriate water parameters can cause a lot of stress for shrimp if they are poorly maintained.

In shrimp culture, the most important thing is the consistency of water parameters. Shrimp don't like change.

Ammonia, nitrite, or nitrate,
low oxygen levels,
Insufficient temperature range,
High or low pH,
Hardness: GH and KH.
All of these water parameters can be stressful for the shrimp if they are not within the optimal range. So any changes should be tracked immediately.


Test your water.
Without checking your water parameters, you won't even know what could happen.

You need to have a master test suite to be able to estimate the real condition of the water parameters in the tank.

Dropping shrimp into the new tank is incorrect

Read more: 8 signs your shrimp is under stress

You've just bought a bunch of new shrimp and put them in your tank, only to find out that they've started swimming wildly around the tank, looking like they want to get out.

Unfortunately, improper adaptation is one of the leading causes of death for newly infected shrimp.

Unlike fish farming, where stock and stock adaptation is quite common, we can't do that with shrimp at all.

This can be especially important for beginners who do not understand the importance of this method.

Remember that shrimp don't like change?

It's basically the same problem but in a different angle. Shrimps are quite sensitive animals. Sudden changes in the chemistry and temperature of water are very dangerous.


We need to acclimatize them before adding them to the tank.

The idea is to introduce the new shrimp slowly with the water in the tank until they are fully acclimatized and can live well in the tank again.

See the article " How to put shrimp in a new tank ".

Big water change

Large water changes (more than 20%) often cause shrimp to swim all over the tank. It is a fact but why?

Assuming that the new water doesn't contain any harmful chemicals, then there is only one reason – a large water change affects the water parameters in the tank.

And what's worse, it happened very suddenly for the shrimp. The downside is quite significant, large water changes will likely:
– Prevent them from molting (“open-necked shrimp”),
– causing them to molt early can lead to death in severe cases.

Note: Some aquarists may say they've changed 25 and even 50% of water and it's fine. It can be rightly said, for example, that the Cherry shrimp is considered one of the most buffalo shrimp species.

However, being good and growing are completely different things. It is not necessary to check their limits.


Shrimps require a stable environment to thrive. Along with this topic, try not to make sudden large water changes.

But, what can we do if we have to do a major water change for… any other reason?

In this case, instead of doing one major change, slowly drip fresh water into the tank to give them time to adjust before the change becomes more significant.

Copper, Hydrogen Sulfide and Other Poisons

Toxic substances come into contact with the shrimp through the gills rather than the skin (hard shell), which is a much more direct and dangerous way of absorption.

Toxins go directly into the shrimp's bloodstream without being filtered by other parts of the body that could be used to protect against them.

This means that toxic levels can quickly weaken the shrimp, leaving the shrimp vulnerable to disease and other pathogens if not treated appropriately right away.

In many cases, the cumulative effect of the toxins can be revealed by behavioral changes – shrimp quickly respond in the form of increased mobility.

The list of toxins that any shrimp farmer should be aware of includes:

Refer: How to Kill Instant Water in Shrimp & Aquatic Ponds

Copper pollution (Cu, even in small amounts can be deadly).
– Hydrogen sulfide (H2S, it smells like rotten eggs).
– CO2 poisoning (CO2 concentration in excess of 25-30 ppm is very dangerous for shrimp).
– Chlorine, chloramine, heavy metals (These chemicals irritate gills and block oxygen-carrying cells, resulting in shrimp suffocation).
- Pesticide.
– Medicines and fertilizers (Some aquarium additives may contain copper, or other toxic elements. So they must be used with caution).


Read product description. Many manufacturers will call their products will tag their products as 'safe shrimp' but you must research the ingredients of these products and choose the most suitable for your aquarium.

Check everything. The only way to prevent pesticides is to quarantine everything and especially the plants before putting them in the shrimp tank.

Provide enough oxygen. Hydrogen sulfide can be effectively neutralized in tanks with oxygen. Once hydrogen sulfide gas connects to oxygen, it reverts to its sulfate, non-toxic form.

Contaminant binder. Age and treat your water with a water conditioner before use. Doing so will eliminate this problem in the first place.

Parasites or disease

In some cases, shrimp that are sick or have severe parasites will cause the shrimp to react wildly in the lake.


Unfortunately, there are not many diseases and parasites that we can successfully treat in the shrimp tank.

Some methods are very risky and do not guarantee any results.

Incompatible tank mates

In my experience, one of my tanks has been invaded by a dragonfly larva. I can't understand why my shrimp don't want to spawn. Also, their behavior is a bit weird.

Although they do not rush from side to side of the tank, they react very quickly and jump at any moment.

It took me weeks to find the culprit! Then the behavior of the shrimp becomes normal.

I believe shrimp can sense predators even when they can't see them and that can influence their behavior as well.


Be very careful with other species in the shrimp's tank. Avoid or do not keep shrimp with:
– Larger or aggressive fish (the shrimp will start to hide).
– Any crayfish species (be ready to lose some).
– Most freshwater crabs (sometimes may lose some shrimp).

Could swimming be a simple trait of shrimp?
- Not impossible. It is true that dwarf shrimp are quite active animals and always move around the tank in search of food. However, unlike fish, crayfish and crabs, they have no personality in most cases. The behavior of the shrimp is quite standard.

How to distinguish shrimp mating behavior from signs of stress?
– You need to watch the other shrimp. Other females or older females do not participate in this frenetic dance. They will continue to do what they normally do, eat.

However, if you have any doubts, if the shrimp start swimming around the tank right after you change something (feeding them, fertilizing plants, changing the water, planting plants, introducing new pets) , etc) – that can be a very bad sign. .

Shrimps can swim around the tank for two main reasons, which can be:

Some form of mating or stress response.
You need to understand their requirements and know when the shrimp are happy. It will allow you to notice any erratic behavior before it's too late.

So, if you see your shrimp swimming frantically, it could be a sign that something in the water is not good for the shrimp.

You must solve it immediately!

First things first – remember what the last thing you did was and change it out if possible.
Check your water parameters for ammonia, nitrite, and nitrate.
If you have ammonia, nitrite, nitrate or copper poisoning – change the water first.
Make sure that the pH, GH, KH and temperature do not fluctuate.
Ideally, you need to have an isolation tank ready at all times.

Refer: How to Remove Snails from Shrimp Pond – Aquarium

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