Shrimps are invertebrates, and like most invertebrates, they have a skeleton on the outside in order to protect themselves. Molting is the process by which a shrimp sheds its thin shell and starts to grow a new, bigger one to live in.
Adult shrimp will molt every three to four weeks if they are healthy. Younger shrimp will molt more often because they grow so quickly, maybe every one or two weeks.
It’s very important that the water parameters are kept consistent for newly molted shrimp. Once they break through their hard shell, they’ll take in water to get a little bigger and then wait for their new shell to harden in the next size up. For more information about why this is important, read the water changes section.
Molting is also needed for breeding to happen. When a female shrimp sheds her hard shell, she sends out a pheromone that makes males want to mate with her. See the molting behaviour section for more detail.
As a shrimp gets ready to molt, there are a few things you can watch out for in the way they act. A person is most likely showing signs when they spend a lot of time standing still and not moving for at least an hour. They sometimes won’t even eat while doing this, they’ll just remain motionless, only slightly moving their antennae. If you see a lot of shrimp acting this way, it could mean that the water quality is bad. You should test the water and make any necessary changes. As long as there aren’t too many shrimp that are still, you should be able to come back in a few hours and see a new molt.
They hide for a few days until their shell has had a chance to harden again after molting because they are very soft and easy to hurt. It’s common for tank owners with few fish to see molts but no shrimp.
Females start breeding when they shed their skin and release pheromones into the water that make males want to mate with her. This will make the sexually mature males swim quickly around the tank, doing laps, to look for the female that has just shed her skin and is hiding. The eggs will move from her saddle to under her body and stay there until they are ready to hatch. This happens when a male finds the female and they mate. See the Breeding Cherry and Crystal Bee shrimp article for more information on this subject.
Knowing how the molting process works at a basic level makes it clear why stable parameters are so important.
When a shrimp has just shed its shell and is taking in more water to grow, it is more likely to experience osmotic shock. Osmosis is the movement of water from a low concentration to a higher concentration. In real life, this means that if you change the water in your shrimp tank and add softer water, the softer water will try to mix with the harder water that they have already absorbed. This can make their cells grow too big, which could be harmful or even kill them. The opposite can also happen. But if you move the shrimp from soft water to harder water, they will quickly take in more minerals.
Shrimp keeping is an enjoyable hobby for aquarists of all levels. However, one aspect of shrimp care that often confuses beginners is molting. When shrimp molt, they shed their outer shell to allow for growth. This leaves behind an empty shell that looks like a dead shrimp! So what happens to this shed exoskeleton? Do shrimp eat their molt?
What Is Molting?
Molting is a natural process where shrimp shed their outer shell, called an exoskeleton. This allows the inner soft tissue to grow larger before hardening into a new shell.
Shrimp molt frequently when young to facilitate rapid growth. Adults molt less often, around every 1-2 months, to replace worn shells or regenerate lost limbs.
The molting process has 4 main stages
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Pre-Molt The shrimp’s new shell starts forming underneath its current one Its appetite decreases as energy is focused on molting.
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Molting: The shrimp absorbs water to split open its old shell, then wriggles free.
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Post-Molt The new soft shell hardens over several days The shrimp is vulnerable during this stage and often hides.
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Inter-Molt: The shrimp resumes normal activity with its larger shell until the next molt.
Do Shrimp Eat Their Molted Shells?
The answer is yes! Shrimp commonly eat their molted exoskeleton to recycle the nutrients and minerals contained within.
Eating the molt returns some of the calcium and other minerals that went into producing the shell. This helps the shrimp replenish its reserves faster to build the next exoskeleton.
Shrimp also eat the molts of tankmates. The shed shells contain protein, which is beneficial for growth and breeding.
In the wild, shrimp may eat up to 50% of their molted exoskeletons. However, aquarium shrimp often do not consume the entire molt before it disintegrates.
Why Do Shrimp Eat Their Molted Shells?
There are 2 key reasons shrimp eat their molted exoskeletons:
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Regain minerals: The old shell is made of calcium carbonate and chitin. Eating it returns some of the calcium and minerals used to produce the shell. This helps the shrimp replenish its reserves faster after molting.
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Nutritional value: The molted shell contains protein. Shrimp need protein in their diet for tissue growth and reproduction. Eating the molt provides an excellent source of protein.
Consuming the shed exoskeleton allows shrimp to recycle resources back into their bodies. This supports the energy-intensive molting process and subsequent growth.
When Do Shrimp Eat Their Molted Shell?
Shrimp will start eating their molted exoskeleton right away. They are very opportunistic eaters and won’t waste potential food sources.
However, shrimp are also vulnerable immediately after molting while their new shells harden. So they might wait until fully hardened to start consuming the old shell.
Shrimp continue nibbling at molted shells for up to several days after shedding until it fully disintegrates or other clean up crew eat it.
Do All Aquarium Shrimp Eat Their Molts?
The majority of common aquarium shrimp will eat their shed exoskeleton, including:
- Ghost shrimp
- Cherry shrimp
- Amano shrimp
- Bamboo shrimp
However, some shrimp species are less likely to consume their molted shells, such as vampire shrimp. Their feeding behavior focuses more on catching live foods.
Molting behavior can also vary slightly between individual shrimp. Some are messier eaters that leave more debris behind. But most will eat at least part of their molted shell.
Should You Remove Molted Shrimp Shells?
You don’t need to remove molted shrimp shells from the tank. In fact, leaving them in allows the shrimp to recycle the nutrients by eating their exoskeletons.
However, unsightly shells littering the tank bottom can bother some aquarists. In that case, use tweezers to remove any unsightly molts within reach. Just leave some shells for the shrimp to eat.
Shrimp also feel vulnerable after molting and appreciate having hiding spots. Provide plenty of decor like plants and rock caves.
Signs of Healthy Molting
Regular molting is a sign of healthy shrimp. Here are 3 clues your shrimp are molting properly:
- Shrimp hiding more than usual as they prepare to molt
- Empty translucent exoskeletons left behind
- Increased appetite and activity post-molt
Seeing these behaviors means your water quality and diet support natural molting. Keep up whatever you’re doing!
Problems With Molting
Issues with molting can occur if the diet or water parameters are unsuitable. Here are 2 common molting problems:
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Failed molts: The shrimp struggles to free itself from its old shell and dies stuck inside it. This often results from low calcium levels.
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“White ring of death”: A white band appears where the new shell has hardened prematurely under the old one. The shrimp cannot escape its old exoskeleton and perishes.
Test your water routinely and provide a varied, calcium-rich diet to prevent molting complications.
Supporting Healthy Molting
Here are 5 tips to help your shrimp molt successfully:
- Maintain stable water parameters, especially calcium hardness.
- Offer nutritious foods like blanched veggies and calcium-fortified shrimp pellets.
- Provide ample hiding spots among plants and decor.
- Don’t overfeed to prevent fouling the water.
- Avoid large water changes that alter parameters suddenly.
Do shrimp eat their molt?
The turtles will happily eat their old shell if you leave it in the tank. It contains a lot of calcium, which helps them build a new exoskeleton.
It’s almost certain that every shrimp keeper will have a bad molt at some point; it’s a pretty common reason why shrimp die. The vast majority of molting problems can be pinned on two key reasons: water parameters and diet.
Most likely, the main reason the molt didn’t work is that the water conditions aren’t right for your type of shrimp. The two most important things to look at in water to figure out why molts aren’t working right are the General Hardness (GH) and Carbonate Hardness (KH).
Total Dissolved Solids (TDS) is another parameter that is often used. It is a less accurate way to summarize the chemistry of the water and can vary a lot with tap water depending on where you live.
If you notice deaths in your colony soon after changing the water, read the section on water changes for ideas.
Our Shrimp Suggester tool can help you to check your water parameters are optimal for your shrimp.
Their diet, which is usually high in calcium and protein, is another less common but possible cause of molting problems. Try giving your shrimp a variety of foods, like algae wafers, blanched vegetables, bio film, and foods that are made just for shrimp (e.g. g. Shrimp King Complete).
You don’t have to worry about snowflake food polluting the water because you can leave it in the tank until it’s eaten. The snowflake food, which is made of soybean shells, works by encouraging the growth of mycelia, which are the plant-like parts of fungi. In general, this mycelia has a lot of good nutrients, so it would be a great addition to your diet.
Should you remove molts?
Most of the time, it’s safe to leave the molt in the tank for the shrimp to eat.
You should only remove molts if your fish are infected with parasites or bacteria. If you leave the source of the problem in the tank, parasite eggs or bacteria could be left in the shell, which is not a good idea.
Why shrimp are molting (shedding skin)? Should you remove shrimp molt?
Do shrimp molt?
While molting is typically a good sign that your shrimps are healthy and growing, it’s also essential to keep an eye out for any signs of molting problems to ensure the well-being of your shrimps. Molting is a natural process that shrimp undergo to grow. It involves shedding their old exoskeleton and forming a new one.
What are the side effects of eating shrimp?
Shrimp allergy can be identified from signs and symptoms that appear after consuming shrimp or smelling it, such as itching, the appearance of red plaques on the skin, swelling in the face, especially in the eyes and mouth, and in the throat creating the feeling of a lump in the throat.
Is molting a stressful process for shrimp?
While molting can be a stressful process for shrimp due to their vulnerability during this period, there’s no evidence to suggest that it’s painful. It’s a natural part of their life cycle, much like growing a new set of teeth is for humans. However, ensuring a stress-free environment and proper nutrition can make the process easier for them.
Are shrimp molts dead?
Shrimp molts are often mistaken for dead shrimp. If you notice an empty shell, that’s likely a molted exoskeleton. However, a lifeless body could indicate illness. Why do shrimp eat their molts?