Dwarf shrimp and Molting problems. The White Ring of Death

Shrimp The White Ring of Death

I bet that any shrimp breeder had a situation than one day the shrimp were active and acting normal and then – what is this ring on my shrimp? Unfortunately, “The White Ring of Death” means that your shrimp is in grave danger.

The White Ring of Death is the sign of molting issues. There are many possible reasons that can cause this problem. However, all of them can be reduced to water changes (water parameters kH, gH, pH, and TDS) and diet (protein and calcium).

Therefore, if you see “The White Ring of Death” it is mandatory to check and double-check everything in your aquarium. In most cases, it is a combination of all these factors. So, let’s take a look at each of them.

I would like to stress that you should not add anything to the water until you test pH, KH, GH, TDS. Anything affecting the water balance will affect molting. 

What is The White Ring of Death?

Shrimp The White Ring of DeathThe White Ring of Death is the result of unsuccessful molting.

So, how it happens. During molting, the shrimp is filling its shell with water until the old exoskeleton bursts at the breaking point in the neck area (between the carapace and the first abdominal segment). At the same time, the shrimp U-bends (spring effect) and wriggles off the old shell.

This is where the problem comes.

Instead of breaking at one point in the neck area, the shell breaks across the full exoskeleton. The “ring” is exposed flesh of the shrimp.

As a result, there are two parts of the old exoskeleton, which do not have any connection.

Therefore, U-bends do not help and shrimp cannot pop out of the shell.

In some cases, it seems that shrimp can barely move their legs or mouth. That is because the old shell is not attached to the shrimp body as it used to.

Imagine that you have taken off the glove partially. You can move your fingers inside but it will not affect the glove. Eventually, it stresses the shrimp and it dies in one or two days.

Note: There is still a small chance that shrimp will be able to get out of the shell.  

Shrimp, Protein and Molting Problems

Well, I have seen so many times people saying that too much protein can cause the shrimp to grow too fast. As a result, it becomes really hard to shed off the shell and they can get “The White Ring of Death” or some other molting problems.  

Frankly saying, some time ago I also thought this way.

However, now I have my serious doubts that protein can cause this kind of molting problems. What I mean is that the protein problem is exaggerated. 

I need to mention that fast growth can cause deaths. However, it is a little bit different. The faster shrimp grows, the more often it molts. Because molting is a very dangerous procedure by itself, every time shrimp molt, they risk.

Therefore, mathematically there is a higher chance to fail. Nonetheless, it has nothing to do with “unusual overgrowth”.  

Shrimp need a lot of Protein

The point is that I have read like several dozens of different studies about dwarf shrimp. To my surprise, almost in all cases, the researchers fed shrimp daily with food that contained 40-47% of crude protein.

Even more, some of these studies lasted months and they did not mention any problems with molting. On the contrary, right now it seems to me that, for biologists, it is a universal approach to feeding shrimp.

Why? Because it provides the best shrimp growth for their experiments without negative effects.

In addition, I would like to remind that exoskeleton consists of the three main components:

  1. Chitin (20-30 %).
  2. Protein (30-40%).
  3. Calcium carbonate(30-50%).

As we can see, protein plays a fundamental role in shrimp life. Therefore, when some shrimp breeders blame protein, well, I cannot accept it anymore unconditionally.

We do not know it for sure. It is just the guess. In order to become a problem, we need to give our shrimp mostly protein food and nothing else. Which is theoretically possible, but very unlikely in reality.

Based on everything that was said, the problem is not just protein, the problem is the diet itself. Maybe your shrimp are lacking something.

Shrimp need food diversity to get all microelements for a healthy life.

Thus, if nobody can pinpoint why they are dying, you need to change their diet. In this case, you can temporarily switch to vegetable-based foods (blanched kale, spinach, or zucchini) and feeding sparingly. However, keep in mind that shrimp can live without protein only for a short time.

One of the most successful shrimp breeders on YouTube had this situation. Guess what happened next? His colony of Crystal Red Shrimp turned cannibalistic!

They need protein and if you do not give it to them, they will solve the problem in their own way. 

Water Changes and Molting Problems

Some shrimp breeders believe that the reason for “The White Ring of Death” is water changes. It is a sign that you are doing too large or too many water changes.

Actually, I completely agree with that if water changes alter the parameters in a major way and cause a forced molt even if shrimp are not ready.

Therefore, we need to pay close attention to KH, GH, pH, and TDS. Remember that the most important thing for shrimp is consistency. 

Shrimp, pH, and Calcium

In one of the experiments, shrimp were exposed to reduced pH for 21 days. The results showed no differences in exoskeleton growth (percent increase in carapace length), but the calcium weight percent of their shell changed significantly in reduced pH conditions, resulting in a greater calcium and magnesium (Ca:Mg) ratio. 

These results suggested that even short-term exposure to pH reduction can significantly affect exoskeleton mineralization. The metabolic investment in increased calcification may come at the expense of other physiological processes (such as reduced growth and increased mortality).

As the mineral content of the exoskeleton increases, so too does the density of the exoskeleton, which can cause molting problems. 

I highly recommend reading my article “How to Supplement Shrimp and Snails with Calcium”.

Shrimp, gH, and pH

General Hardness is the measurement of the level of dissolved minerals in the water. It is predominantly represented by calcium and magnesium but also contains other mineral ions.

GH is extremely important to shrimp because Calcium Carbonate is vital in a shrimps molting process.  In order to successfully molt, they need to have enough Calcium Carbonate in the water for them to absorb and to create a strong and healthy new exoskeleton in the molting process.

As I have written in another article “approximately 20 to 25% of the total body-calcium will be absorbed from the old shell”. The rest 75% of the needed calcium depends on nutrition and minerals in the water.

However, lots of people forget about Magnesium in this equation. Magnesium, actually, helps shrimp to absorb Calcium Carbonates. Ideally, we should have a ratio:

  • 4:1 (gH:Magnesium)
  • 3:1 (Calcium:Magnesium)

Mg = ((GH*17.86) – (Ca*2.5)) /4.1

To summarize a little bit – Hardness is a measure of water’s calcium and magnesium. Calcium and magnesium are very important to freshwater shrimp in keeping exoskeletons strong.

When hardness is too low shrimp will take a longer time after a molt for the exoskeleton to harden. While soft shrimp are vulnerable to mechanical damage. Also, shrimp exposed to soft water is more susceptible to other water quality conditions also. Very hard water can also be a problem.

You can read more about “Aquarium: Molting Process and Metabolism of the Dwarf Shrimp” right here. 

Low Calcium and High Calcium in Shrimp Tank

Some aquatic brands use Calcium sulfate (CaSO4) in their products because (as they say) it helps to stabilize pH. However, there is a downside. Calcium sulfate buffers the water with huge amounts of calcium. Basically, you will have an overdose of calcium in your tanks.

Too much calcium causes the water to become hard, as reflected by the high gH reading. As a result, hard water will affect the shell of the shrimp, because it will become more rigid. Thus, it will take your shrimp lots of energy trying to molt. It stresses them a lot and can lead to death.

On the other hand, if you put them in a tank that has much softer water than what they are used to, their exoskeleton becomes too flex and malleable. As a result, it may not crack at all or the underlying layer of the shell will be too weak and shrimp will die during a molt or shortly after that. 

Tip: if you have soft water, instead of adding calcium blocks you can add cuttlebone. The point is that calcium blocks dissolve a lot faster in the soft water potentially causing overdosing with calcium.

In addition, if you need to save your shrimp like right now, lots of shrimp breeders do not recommend mineral stones because most of them do not degrade enough to make a difference. 

Blanched Kale vs Molting problems

This is a great product, which can help us to provide our shrimp with additional microelements. Lots of shrimp breeders recommend giving shrimp blanched vegetables, especially the kale if you see that some other shrimp have problems with molting.

Kale is very high in calcium, vitamins and additional nutrients. Within one or two days, the shrimp will get enough microelements for preventative measures.

I have made a comparison of the most popular vegetables.


Nutrition value per 100 g.

  Cucumber Zucchini  Kale
Energy 15 Kcal 17 Kcal 35 Kcal
Carbohydrates 3.63 g 3.11 g 4.42 g
Protein 0.65 g 1.21 g 2.92 g
Total Fat 0.11 g 0.32 g 1.49 g
Dietary Fiber 0.5 g 1 g 4.1 g
Folates 7 µg 24 µg 62 µg
Niacin 0.098 mg 0.451 mg 1.180 mg
Pantothenic acid 0.259 mg 0.204 mg 0.370 mg
Pyridoxine 0.040 mg 0.163 mg 0.147 mg
Riboflavin 0.033 mg 0.094 mg 0.347 mg
Thiamin 0.027 mg 0.045 mg 0.113 mg
Vitamin A 105 IU 200 IU 4812 IU
Vitamin C 2.8 mg 17.9 mg 93.4 mg
Vitamin K 16.4 µg 4.3 µg 389.6 µg
Sodium 2 mg 8 mg 53 mg
Potassium 147 mg 261 mg 348 mg
Calcium 16 mg 16 mg 33 mg
Copper 0.28 mg 0.37 mg 0.053 mg
Iron 13 mg 18 mg 1.60 mg
Magnesium 0.079 mg 0.177 mg 33 mg
Manganese 24 mg 38 mg 0.920 mg

The Egg Shells, Calcium and Shrimp

Shrimp needed calcium to molt properly. Therefore, if you do not have any calcium supplements around (for example like highly recommended cuttlebones) there is always a way out!

The Egg Shells will give your shrimp enough calcium. Bake the eggshells in the oven for a few minutes. It will kill any bacteria on the shell and it will help to turn it into a fine powder. Then, take the eggshells and crush it to powder (use a mortar and pestle).

Do not add too much, just a pinch will be enough. 

Molting Problems and Manual help

It is very sad to see your shrimp suffering. Sometimes people decide to step in and help the shrimp. The logic is simple. If certain death awaits the shrimp anyways, it might be worth it to try.

I would like to warn everybody. Shrimp have a very delicate body. Any operations with tweezers require almost surgical precision. In all other cases, shrimp have better chances of survival without your help.

Frankly saying, I have never heard that this kind of “assistance” ended well. In a best-case scenario, people simply break the shrimp’s legs or crash they carapace, increasing shrimp suffering even more.

Hope for the best and let nature take its course.  

Preventative Measures against Molting Problems

  1. Do not do big and (or) frequent water changes (10% water change every week or two is good enough). The bigger the water change you do the more things come into effect. An aquarium is a very complex and fragile eco-system.
  2. Do not buy adult shrimp. They have a hard time of acclimatizing compared to juveniles. Find out everything about water parameters and try to duplicate them. After that, slowly change to what you want them to be.
  3. Use remineralizers.
  4. Best way to “maintain” TDS between water changes is to top off with RO/DI water.
  5. Stop dosing the tank with CO2. This could also be causing problems. Read more about it in my article “CO2 in a Shrimp Tank”.
  6. Driftwood can also change water parameters (drop the pH) if you have one.
  7. Check the diet.

28 thoughts on “Dwarf shrimp and Molting problems. The White Ring of Death

  1. Easy but very informative read.

    Some reading is tough going for the beginner, way too much science references etc.

    I should have had s beer reading this. Thank you very much

    Mr Bob

    Thank you indeed

    1. Hi Mr Bob,

      I really tried my best to explain this problem. However, sometimes I do get carried away with facts)).
      Thank you for the response.

      Best regards,

  2. As a person who is having this issue since last 10 days, I appreciate this amazing article. I already lost 7 out of my 10 shrimps due to white line issue and I will probably lose 2 of them more in a few days because they have white line too. I wish I had come across to this article before :/ However, my shrimps were not eating zucchini or food I give them. Only one of them has been eating and I assume that it is gonna be the only one which will stay alive. I think this also supports the importance of diet as you shared.

    1. Hi Ugur,
      Sorry to hear that. I hope that you will overcome the problem, eventually.
      Regarding vegetables. I think that they simply have way too many other goodies in your tank. Try to change their diet.
      Best regards,

      1. Thanks for your reply. Well, I have plenty of different diet options but they do not really prefer to eat. I do not know what else I can do besides adding different types of food into the aquarium.

        You wrote that the best way to “maintain” TDS between water changes is to top off with RO/DI water. I also read that this may shock the shrimps and we should be careful while doing this. What do you think the ideal amount of topping of with RO/DI water not to shock the shrimp?

        1. In my article about TDS I also mentioned that I am not a big supporter of topping off with RO/DI water without minerals. However, I also know that there are succesful shrimp breeders who do that. Personaly, if I had to, I would not do more than 5%.
          Best regards,

    1. Hi June,
      Sudden temperature fluctuations can trigger molting when shrimp are not ready.
      That is why when we do water changes, we have to pay attention to the temperature. There should not be any differences.
      In addition, this is also one of the reasons why we acclimate dwarf shrimp.
      Best regards,

  3. Just came across your article while searching how to fix moulting problems. Thanks for the info! I’ve been giving my guys calcium tablets daily (1/4 or less of a tab). Now I’m thinking the are getting too much calcium and they can’t break their exos (they have white ring of death on adult females) . GH is around 5 or 6. KH at about 4. Everything else is zero, except nitrates are 5. Going to just give them their crab cuisines, veggie rounds, shrimp pellet and supplement with broccoli and Kale. Going to cut out the calcium tabs. I have cuttlebone in there so it’s probably enough. Using seachem equilbrium to bump up the GH>

  4. Gr8 article! Just starting with blues (5). Haven’t been successful in the past, however I’m trying to get it right.

  5. Nice Article. Kh is mentioned once or twice in the article, but no real guide lines or scientific points regarding kh. Is kh important for shrimp?

  6. Whilst it is unlikely that a shrimp will survive long after developing a white ring, it’s not a death sentence. It is possible that the shrimp could still escape from the outer shell and go on to live a long, happy life.

    1. Hi Jazalyn,
      It is true, unfortunately, these cases are more of an exception than the rule. 🙁
      Best regards,

  7. I’ve been dealing with this problem and it’s turned quite bad. Almost every adult female I have is dead. However, the adult males and shrimplets are completely fine. I’m going to try the eggshell treatment. Is there anything else you can recommend?

    1. Hi Omar,
      This is strange.
      In my experience, the molting problem does not depend on gender.
      Are you sure that they were not harassed way too much?
      Take a look at my article “Male to Female Ratio in Shrimp Tanks“.
      Best regards,

  8. that was veery very helpful!
    Thank you for the very simple, easy to understand info! Please keep up the great work so we can keep learning 🙂

  9. My shrimp lost its head! Does the white ring of death cause them to lose their head?

    1. Hi Jade,
      No, I have never seen it before.
      Probably it was eaten after its death.
      Best regards,

  10. Amazing article, thank you!
    Is the white ring predominantly a sign that there is too much calcium in the water? I have about 2 inches of crushed coral as substrate (tank was not originally set up for shrimp) and I think the shells of the new adults I bought are getting too hard to molt. They are all lasting about 1-2 weeks before getting the ring and dying. I have a gh/kh tester in the mail but trying to remedy this before it’s too late for all the little guys.
    Thank you again for the resource and knowledge share for the community!!

    1. Hi David,
      What species do you have?
      I presume that you are talking about Neocaridinas. If so, in my experience, it should not be the problem. Neocaridinas are not finicky and can tolerate hard water pretty well, unless it is extremely hard.
      You need to test all your water parameters ASAP!
      Without it, it is not possible to say almost anything. Sorry.
      Best regards,

  11. Let’s say I was making a miscalculation on how much remineralizing salt to use and I started having white ring of death losses after a couple months of shrimp stewardship.

    I discover my GH is 12+ and KH is 6 – tds is around 320. All my fault due to silly error – I use R/O and salty shrimp gh+/KH+

    I made some new water with a tds of 150 and did a 10% water change. That brought my TDS down to 300.

    I want to save my shrimp – how do I quickly and safely bring that gh closer to 8 and KH closer to 4? Some continue to molt fine but I am still suffering losses and the GH makes the most sense to me as the cause!

    1. Hi Ethanielson,
      >I want to save my shrimp – how do I quickly and safely bring that gh closer to 8 and KH closer to 4? Some continue to molt fine but I am still suffering losses and the GH makes the most sense to me as the cause!
      Unfortunately, it is not a math. It is not possible to guarantee the best result with the minimum damage.
      Nonetheless, I would still keep doing weekly 15-20% water changes with TDS between 100-150.
      To reduce stress level – do water changes VERY slowly. The drip method (3-5 drips per second) will be even better. The slower the better!
      Best regards,

  12. Hi Michael,

    I just introduce my shrimp to their cycled tanks (with moss and a think layer of black sand). I found 1 or two died each day for somes days now, and majority of them had the white ring. I also found successful molts in the tanks as well. All my tank set ups are the same, but I found only 2 deaths for fire reds, 1 death for blues but most deaths happens for yellows and snow balls. Nitrate levels are okay and nitrite, ammonion checks out, however I have a ~1 dGh and 17 dkh. Are they dying because of the high kh? I add really small coral (1-2cm) to each tank but gh didn’t seem to rise. Or are they just dying because of the regular die off from the change of new environment? I acclimate them very slowly over 2hour+ period and didnt see signs of stress when finally introducing them to the tanks. My tap water has 6 dGh and 13 kh (didn’t seem to fluctuate much), I don’t know why gh drops in the tank and kh raises. How could I decrease kh and increase gh at the same time? Do you have any suggestions for me? Really need some help.

    1. Hi Silvia,
      Your shrimp are atrying to survive in your water parameters. Sorry.
      I would strongly recommend to check out my article about GH.
      The disparity between GH and KH is too big in my opinion. It will be extremely difficult to fix.
      You need to use RO/DI water and remineralizers.
      Best regards,

  13. Recently it has been shown that mitochondria actually transmute metals and it is why chickens on a zero calcium diet still make calcium for their shells. Remove potassium from their diet and they no longer make calcium. The things we don’t know about biology yet could fill many universities with books till they burst.

    1. Hi Bob,
      This is interesting!
      Best regards,

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