When shrimp molt, they replace their old shell with a new one. This happens at every stage of their life. This is because shrimp are crustaceans whose body surface is covered by an exoskeleton called a cuticle.
The molting process is often the thing that most farmers worry about. Although shrimp are more likely to get sick during this stage, the molting process will always happen as the shrimp grows up.
Let’s get to know in more detail what molting is and how it’s done in this article!
As an aquarium hobbyist and shrimp enthusiast, I’m fascinated by the unique lives and behaviors of these cute little crustaceans. One of the most interesting things about shrimp is that they molt or shed their exoskeletons as they grow. This process allows shrimp to increase in size after their existing shell becomes too constricting. But why exactly do shrimp molt and what does the molting process entail? In this article, we’ll take a deep dive into the shrimp molting cycle so you can better understand this crucial part of your shrimp’s growth and development.
Why Do Shrimp Molt?
Shrimp, along with other arthropods like lobsters, crabs, and crayfish, are equipped with a hard, protective exoskeleton on the outside of their bodies. This shell is made up of chitin, a tough protein-carbohydrate complex that offers security against predators The only problem? This unyielding exoskeleton doesn’t allow for any growth!
That’s why shrimp have to shed or molt their shells regularly as they mature. Molting enables the shrimp to swell in size before developing a brand new larger shell to live in. Without this important process, shrimp would remain confined to the same size exoskeleton forever. No bueno for a growing invertebrate!
Typically, each individual shrimp will molt every 1 to 3 weeks depending on its age. Younger, actively growing shrimp may molt as often as every 4-7 days. Older adult shrimp molt less frequently, like every 3-4 weeks. Females also molt right before breeding in order to release pheromones into the water to attract mates.
The Shrimp Molting Process Step-By-Step
Molting is an elaborate, energy-intensive process that shrimp have to undergo to keep growing Let’s break it down step-by-step
1. Separation from the Old Shell
The molting process begins when the shrimp extracts itself from the innermost layer of its old exoskeleton, called the endocuticle. To separate from the shell, the shrimp absorbs water to expand its body and this forces the shell to crack along the thinner membrane at the carapace (upper shell).
2. Crawling Out of the Old Shell
Once the carapace has lifted, the shrimp will wiggle and crawl out of the rest of its old shell through the opening, leaving its exuvia or shed exoskeleton behind. This empty shed shell is what you’ll often notice left behind in your tank after a molt.
3. Expansion & Absorption of Water
Free of its rigid exoskeleton, the now soft, vulnerable shrimp will gorge itself on water over the next several hours. This rapid water intake causes the shrimp to swell up to 40% larger than its previous size!
4. Development of the New Shell
After reaching its maximum post-molt size, the shrimp stops water intake and the new exoskeleton begins to harden and take shape. The shrimp will hide during this time to avoid predators while its new shell fully hardens and mineralizes over 12-72 hours.
5. Shell Hardening Completed
Once the new shell has fully hardened and mineralized with calcium and other elements from the water, the shrimp will emerge from hiding with its new larger exoskeleton! The shrimp can now resume normal activities like swimming, eating, and socializing.
Molting Issues and How to Help Your Shrimp
For the most part, shrimp molting is a routine process that occurs without issues. However, you may encounter problems like failed molts, deaths after molting, white ring disease, or shrimp getting stuck mid-molt.
Here are some tips to reduce molting problems:
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Maintain excellent and stable water quality. Fluctuations in pH, KH, GH, and TDS from water changes can shock shrimp during delicate molting stages.
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Avoid handling or disturbing shrimp before, during, or after molting when their shells are soft.
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Provide a nutritious diet with calcium from foods like shrimp pellets to support new shell development.
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Give adequate hiding spaces like moss or decor so shrimp feel secure molting.
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Use minerals like Seachem Equilibrium if your GH is less than 6 to improve shell hardness.
How Often Does Molting Occur?
Under healthy conditions, adult shrimp molt or change their skin every 3 to 4 weeks. However, younger shrimp will change their skin more frequently, every 1 to 2 weeks, to be precise. This is because young shrimp experience a faster growth process.
Meanwhile, replacing old shells with new shells in shrimp only takes a few hours.
Molting Process in Shrimp
The molting process in vannamei shrimp is divided into four stages: post-molt, molting, inter-molt, and pre-molt.
Post-molt is the phase in which the shrimp’s exoskeleton has just been shed from the last molt. Usually, in this phase, the shrimp will absorb a lot of water to strengthen their new cuticles.
Molting is the phase when the shrimp begins to shed its outer shell. In order for the shrimp’s exoskeleton to fall off completely, it will loosen up and begin to move out of its old body.
During this phase, the shrimp takes in more protein and minerals, which makes the exoskeleton getting harder. Meanwhile, shrimp appetite is not disturbed and even tends to increase.
Pre-Molt is when the shrimp prepares for the following molting process. The cuticle layer will slowly grow and be visible to the naked eye. Usually, in this phase, the shrimp appetite will decrease than usual.
Also Read: 5 Types of Shrimp Pond Aerators and Their Function
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.
How do you know if a shrimp is molting?
Shortly after adult females molt, they also release pheromones into the water, telling the males that it’s time to breed. If you have a large colony of shrimp, you may notice the males swimming around erratically trying to find the female. Anyway, if your shrimp are molting, it means that they are growing, which is a good sign!
Why did my shrimp molt fail?
The main reason for a failed molt is likely because the water parameters are not optimal for your species of shrimp. The two most important water parameters to check when trying to identify the cause of bad molts are General Hardness (GH) and Carbonate Hardness (KH).