How to Supplement Shrimp and Snails with Calcium

How to Supplement Shrimp and Snails with Calcium

The importance of calcium for shrimp, crayfish, crabs and especially snails is a well-known fact. Therefore, today I will talk about calcium supplements for shrimp and snail tanks. It is widely understood that they require calcium in unusual quantities during certain stages of their life.

The reason is that one of the main components of the shrimp shell is calcium carbonate (from 30 to 50 %). In snails, it is even more crucial, about 95-98% of snails shell’s dry weight is calcium carbonate (CaCO3) as well.

As we can see, shrimp, crayfish, crabs and snails depend on calcium. Actually, calcium is so vital for them that, according to different studies, they can sense calcium concentration in their environment and prefer to live in a high-calcium environment. 

Importance of Calcium for Shrimp, Crayfish and Crabs

Shrimp, crayfish, and crabs have external skeletons (exoskeletons or shells) that limit the extent of their growth. The only way for them to grow is to molt. The process of shedding their old shell is called molting.

Due to the fact that shrimp molt pretty often (from every few days for baby shrimp to once per month for adult shrimp), they require a lot of minerals to reconstruct new exoskeletons. Therefore, our job is to provide all the necessary minerals for them to make and reinforce their shells.

In one of my articles (Aquarium: Molting Process and Metabolism of the Dwarf Shrimp), I referred to the studies about shrimp exoskeleton main components. According to the researches, about 30-50% of shrimp shells is calcium carbonate. That is a lot!

Note: Like fish, shrimp can absorb calcium from the water and the diet. If there is enough calcium in the water, they will obtain the majority of their calcium through their gills. At the same time, calcium in the diet will cover the deficiency of minerals in the water. Ideally, these two sources of calcium should be in your tank all the time.

Another important thing that many shrimp keepers forget (or do not know) is that you also need to provide your shrimp with Magnesium. The point is that Magnesium keeps the calcium in a dissolved state and helps calcium absorption. That is why there must be a balance between Calcium and Magnesium (ratio 3:1).

You can read more about “Dwarf shrimp and Molting problems. The White Ring of Death” right here.

Importance of Calcium for Snails

Because snails are soft-bodied animals, many of them have invented a complex strategy for maintaining their soft tissues, for protecting themselves against predation and support for internal organs. This strategy relies on the elaboration of an external calcified rigid structure, the shell.

In snails, the demand for calcium is even higher than for shrimp. Their external shell is almost completely made of calcium carbonate (about 95-98%, the remaining 2% mass are compounds of Fe, Mg, Mn, Al, Na, K). Mostly because snails’ shells can have several calcified layers (generally two to five).           

Calcium Supplements for Shrimp and Snail Tanks

If you do not want your shrimp to have molting problems. If you see that your snails are starting to get eroded shells, cracks, holes, or lose their color (turn whitish). The most likely cause is not enough calcium in the water. As I have just said, we need to provide our shrimp and snails with two sources of calcium:

  • From water (water mineralization).
  • From food.

Water Mineralization. What is Mineralization?

In shrimp keeping hobby we often use terms and expressions “Water Mineralization” or “Remineralizing RO water” to create ideal water parameters for keeping and breeding shrimp. Especially, when we prepare water for the water change.  You can read more about it in my article “How to Do and How Often to Do Water Change in Shrimp Aquarium”. But what is mineralization?

Actually, mineralization is a process of mineral deposition into soft tissues, which form a protective shell for snail (exoskeleton – for shrimp). The shell is formed by calcium carbonate and other trace minerals found in the tank. Calcium carbonate is the major component of various minerals.

Basically, we enrich the water with essential minerals, so that our pets could use them. Aquarists simply call this process – mineralization.

In shrimp, during the pre-molt stage, some of the calcium carbonate in the cuticle is partially dissolved and stored inside the body temporarily for reuse in the newly formed cuticle after molting. In the case of crayfish, the calcium carbonate is stored in the stomach as a pair of stones.

Snails have a restricted ability to store calcium carbonate. Therefore, they must consume calcium on a daily basis. At the same time, the calcium content of their normal food is usually insufficient for shell formation. In addition, obtaining sufficient calcium is time-consuming even in calcium-rich environments.

Re-mineralizers for Shrimp and Snails

Salty Shrimp MineralsThere are many options on the market nowadays (For example, Aqua Blue WizardShirakura Liquid MineralsShrimp King Shrimp MineralsBrightwell AquaticsShrimplab MineralsGlasGarten). They are all good re-mineralizers and lots of shrimp keepers use them without any problems.

However, I have always recommended Salty Shrimp products. Salty Shrimp Minerals (GH/KH+ and GH+ (links to check the price on Amazon) are the ideal re-mineralizers for the shrimp in my opinion. We only use them when utilizing reverse osmosis (RO) water or distilled water in our tanks.

These re-mineralizers are already balanced with calcium, magnesium, and other trace elements. Therefore, we do not have to worry about any ratio.

You can read more about Salty Shrimp Minerals (GH/KH+ and GH+) here.

Additional Mineral Sources of Calcium

OK, but what else can we use as calcium supplements for shrimp and snail tanks? Here is the list of the most popular choices of shrimp and snails keepers.

Chicken Eggshells Powder

Chicken eggshells consist of calcium carbonate (~98.2%), and a trace amount of other microelements, i.e. magnesium, boron, iron, manganese, molybdenum, sulphur, silicon, and zinc.  (Shell membranes comprises of 69.2% protein, 2.7% fat, 1.5% moisture, etc).

Chicken Eggshells Powder1. To make eggshell powder, boil eggshells in hot water for 5 – 10 min to kill any harmful bacteria.
Note I know that some aquarists drop untreated eggshells into their tanks. Do not do that! It can wipe out your shrimp colony.
Tip: It easier to remove the membrane if you boil them longer.
2. Let them cool off and dry.
3. Roast them in an oven or microwave for 5 – 10 min to completely dry out and become crispy.
Note: Roasting will remove (burn out) the membrane.
4. If you do not do step #3 – peel the membrane away from the inside of the shells. It can take a while. We remove the membrane so it does not foul the water. Also, the powder will be cleaner without it.
5. Put the eggshells into a coffee grinder and run until they are pulverized into powder (dust).
6. Add some of the eggshells to your shrimp and/or snail tank. That is it. Your little friends will thank you.
Note: At first the powder may float. Do not worry, it will sink pretty fast.

Cuttlefish Bones

Cuttlebone fishThis is another cheap and popular product. You can find it in pet stores (in the bird section). Cuttlefish bones are highly porous, and, basically, just pure calcium. They are also very soft, so just cut off a small piece (1 inch is good for a start) and put it in your tank.

The good thing about cuttlefish bones is that they slowly dissolve in the water and release a ton of calcium which shrimp and snails can use as needed.

Tip: If it floats, tie it down to a pebble and sink it to the bottom (or you can boil it).

Note: Cuttlebone bones dissolve very slowly. Therefore, it will not alter your water parameters fast. It also means that you will not get overdosing. At least, it will give you time to react. Do not place them in filters.

Sometimes it can produce an extremely unpleasant odor because of remaining organic matter in it.

Important: There are 2 types of cuttlebones. One of them contains Calcium Carbonate. Another one is largely Calcium Sulfate. We need Calcium Carbonate one!

Cuttlefish bones – link to check the price on Amazon.

Tums (Antacid tablets)

Tums (Antacid tablets)Some snail keepers claim that they have great luck with the snails eating Tums, but never had success with the cuttlebones. Others claim the opposite. Anyway, these Tums are mostly calcium carbonate and an amazing source of calcium for snails and shrimp. The only problem is that you need to be careful about how much you add.

First of all, they dissolve very fast. Therefore, they can affect the water parameters. To prevent any risk, add ¼ of the tub to see the shrimp (snail) reaction. Second, tums will color the water a little bit for some time. They do not have any other side effects.

Note: According to different observations, shrimp and snails prefer eating the fruit-flavored ones.

Tums (Antacid tablets) – link to check the price on Amazon.

Mineral (Calcium) Blocks

Hermit Crab Mineral BlocksCalcium blocks contain a proper amount of calcium and magnesium. Therefore, they will benefit the health of all shrimp and snails. Compared to cuttlefish bones, calcium blocks dissolve faster and affect GH quicker. They usually do not cloud the water.

Dosage: 4g per 50 liters (10-gallons) to reduce any change in water parameters.

Note: It is recommended that any block remaining after 14 days should be removed and a new one added.

Note #2: Although manufacturers recommend them as a regular addition to the tanks for ultimate long-term health benefits. Mineral blocks are more of a luxury than a necessity.

Hermit Crab Mineral Blocks – link to check the price on Amazon.

Crushed Coral and Crushed Oyster Shells

Crushed-coral-I know that some shrimp breeders use crushed coral or oyster shells. On the one hand, coral and shells have a very high concentration of calcium (carbonate). On the other hand, due to the high amount of salt, it can be dangerous to your shrimp and snails. That is why the main problem with using crushed coral you cannot really control the process. Therefore, you have to be extremely careful not to add too much.

Note: Personally, I would not use them at all in any shrimp or snails tank.

Wonder Shell

Wonder ShellsWonder shells are safe with shrimp and snail. Actually, they will love it from the moment you put in the tank. These shells will raise the water hardness but they will do it slowly. It can take one shell 2 – 4 weeks to dissolve.

Tip: If this is their first exposure, start from the small wonder shell.
Note: Wonder shells have the benefit of clarifying water. In addition, it is much easier and cheaper than messing with crushed coral.
Dosage recommendation: 1 shell per month for 5 to 10 gallon (20 – 45 liters) tanks.

Wonder shell – link to check the price on Amazon.

Food Supplements. Calcium.

Although, cuttlebones, wonder shells, mineral blocks, etc. will greatly benefit your shrimp and snail. Unfortunately, it is still not enough in some cases. You need to use complementary feed for invertebrates (shrimp, snails, crayfish/crabs). 

Mineral Junkie Pearls

Mineral Junkie PearlsMineral Junkie Pearls are an excellent supplement food for all invertebrates. Each pearl contains natural minerals as well as inorganically combined minerals to prevent mineral deficiencies, which cause holes in snail shells, failed molts in shrimp, slow growth and a high mortality rate especially amongst the juveniles.

Along with minerals they also contain vegetable extracts and herbs to provide more nutritional content.

Snails also grow better when they are supplied with an ample amount of minerals, and their shells tend to be smoother and stronger.

Feeding recommendation:

  • 1-2 pearls daily per 15 shrimp
  • 1-2 pearls daily per Crayfish / Crabs
  • 1 pearl daily per 2-5 snails

Mineral Junkie Pearls – link to check the price on Amazon.

Shrimp King Mineral

Shrimp King MineralShrimp King Mineral contains extra minerals. The proven clay mineral montmorillonite, pure calcium-carbonate, and valuable coralline red algae provide all shrimps with plenty of calcium and other minerals as well as essential trace elements. In particular, the natural calcium from coralline red algae exhibits high bioavailability and can be utilized particularly readily by the shrimps.

Unlike crayfish, shrimps must regularly ingest minerals, as they do not have gastroliths (stomach stones) in order to store them. Shrimp King Mineral supports smooth molting and the development of a strong new shell. 

Tip: Shrimp King Mineral is also a good choice for feeding crayfish, dwarf crayfish (CPOs), crabs, and snails.

Shrimp King Mineral – link to check the price on Amazon.

Hikari Crab Cuisine

Hikari Crab CuisineThis is another high in enriched calcium food, which promote shell development and overall good health of our snails, crabs, crayfish, and shrimp. Because of the minerals, Hikari Crab Cuisine contains, they will all love it.

Note: This product will also enhance the color of the shrimp. One of the main components of Hikari Crab Cuisine is astaxanthin. You can learn more about it in my article “How to Enhance Shrimp Color?”

Hikari Crab Cuisine – link to check the price on Amazon.

Mini Veggie Sticks with Calcium

Mini Veggie Sticks with CalciumExcellent combination of ingredients and high level of calcium will make your shrimp hunt for them, once they smell them. Snails love them as well.

Contains a 20% calcium level and 35.0% of crude protein. Probiotics! Ingredients: mixture of plants and vegetables including: seaweed, spirulina, carrots, squash, spinach. Vegetable oils, soy meal, yeast, wheat flour, calcium, vitamin & mineral supplement.

Note: Although they are quite hard sticks, sink quickly and do not float all over the tank. They break down within a few mins. It would be better to use feeding dishes. You can read more about “Everything about Feeding Dishes for Shrimp” right here.

Mini Veggie Sticks with Calcium – link to check the price on Amazon.


I would like to say that re-mineralizers and commercial food should not be the only way to provide calcium. Vegetables rich in calcium must be a part of the shrimp and snail diet for good shell health or molting. Do not underestimate the usefulness of natural sources of food.

There is no need to list all vegetables by mg of Calcium. I will just point out the most popular ones. 

Calcium (mg) per 100gm
Kale 137
Spinach 99
Chinese cabbage 74
Green beans 44
Broccoli 40
Lettuce 33
Carrots 33
Cabbage 32
Pumpkin 24
Zucchini 21
Сucumber 16

 I would recommend blanching them first. You can read about it in my article “How to Blanch Сucumbers and Zucchini for Shrimp, Snails and Fish the Right Way”.

In Conclusion

Calcium plays a vital role in the overall development of the shell, optimum growth and survival of the shrimp, crayfish, crab, and snails.

Depending on the tank set up, we can use different ways of providing calcium for the shrimp and snail tanks. For example, if you are using RO water in the tank. I would not use any additional mineral sources besides remineralizes, special, and natural food sources. If you are using Tap water in the tank, I would use only additional mineral sources (Cuttlebone bones, Wonder shells, Tams, etc.), special and natural food sources.

In any case, do not forget to test your water parameters (PH, KH, GH, TDS read my articles about them) at least every week. If you notice that they are consistently too high or rising, remove additional mineral sources.

How to Supplement Shrimp and Snails with Calcium

25 thoughts on “How to Supplement Shrimp and Snails with Calcium

  1. Hey Michael,
    Thanks for the usefull info. A question though: how much and how often to add eggshell in aquarium?

    1. Hi Ioana,
      It depends on the setup. In some cases, if there are other sources of calcium, you do not even have to add it.
      I would suggest adding a pinch. If shrimp go nuts you can add another pinch next week.
      Just don’t be too overzealous 🙂
      Best regards,

      1. Hi Michael,

        How long does eggshell powder keep? How should it be stored? Or should it only be used fresh?


        1. Hi Allie,

          Free from any impurities (like protein membrane) eggshell powder can be kept for months. Nonetheless, it is recommended to replace it every 4-6 months even if everything seems OK.
          Keep it in a closed glass jar away from the light.

          Best regards,

      2. Hi,

        Do the snails and shrimp eat the egg shells, or is it to increase calcium in the water? Thank you.

        1. Hi Tiffany,
          It is both but mostly for their diet. Because this is their main way of consuming calcium.
          Best regards,

  2. Hi there,
    Can you use a GlyCal tablet?
    It’s a Glycine and Calcium tablet mix..
    Please let me know.


    1. Hi Jay,

      According to some researches, dietary glycine levels increased the survival of shrimps. However, we do not know the safe level or maybe it is absolutely safe at all levels.
      There is no information about it.
      In addition, I have not heard anybody use these tables for shrimp or snails in their aquariums.
      Personally, I would consider it risky.

      Best regards,

  3. If I use bee shrimp gh+ to remineralize should I still add other forms of calcium. I have been recommended the tums method. Will it rise kh? The aquarium is housing 20 blue bolts. 25 gallon cube heavily planted.
    Thank you,

    1. Hi Jacob,
      Do not fix what is not broken!
      If there are no problems with the shrimp why should you add more calcium?
      Tums can affect water parameters if you do it systematically. However, 1 tum won’t change anything.
      Best regards,

      1. Thank you. I’m just new to shrimp. They have been in the aquarium for 9 days. I lost 1 on day 2. I don’t see them often (which I heard is normal). I did find my first molt 2 days ago. I added 1 tum tablet. My water parameters didn’t change much. Just a slight rise in ph .2 or less. KH is still between 1-2

        1. Hi again,
          Welcome to shrimp keeping hobby! 🙂
          9 days is a very short term. Do not force things, just observe. The first month is the most critical with shrimp keeping.
          I would not recommend changing things a lot of things in the tank right now because if there is something wrong it will be hard to find out later and correct them.
          I hope that your tank is cycled.
          Best regards,

          1. Yes the tank is fully cycled and heavily planted. I see them still just less then I did the first 2 days. I’m assuming I just need to be patient.

  4. In what ratio or quantity do I add livestock powdered calcium supplement in to water for snails

    1. Hi Timothy,
      It depends on your setup. For example, if you have hard water your snails may require less calcium supplement if at all.
      We should not forget that fish / shrimp foods also contain calcium, therefore, if their shells look OK, I would add maybe a pitch (as a preventive measure).
      Personally, I prefer to give less than more. It is safer.
      Best regards,

  5. Hello,
    Thanks for the information.
    I have just embarked on a (very very small) snailery. I managed to pick about 250 GALsnails! from my garden in West Africa. Mostly young snails & only 12 large.
    Can I give regular calcium supplements just until I’m able to go mega?lol


    1. Hi Nkiruka,
      Could you provide more information?
      Best regards,

      1. I don’t have an aquarium but rather land snails. So my question is how can I give calcium supplements to ‘land snails’? Thanks

        1. Hi Nkiruka Kaja,
          To provide land snails (like Giant African Land Snails (Achatina sp.)) with calcium, you can use some of the above-mentioned products as well. For example:
          – Cuttlefish
          – Mineral (Calcium) Blocks
          – Powdered egg-shells
          Even more, it is recommended to have cuttlefish bone in their tank all the time! If you want to use powdered eggshells, you can spread it on their food and sprinkle with water. This way the powder will stick to the food or be absorbed.
          Best regards,

  6. Wonderful article, thanks.

    I cannot get hold of Salty Shrimp GH+, as it’s not available locally or at a reasonable postage cost from overseas. So, which are second and third best options please?

    I already have some GH+ by ShrimpLab but there’s no way to tell if it’s any good because it has the same problems as most – no ingredients listed! Totally maddening. It means there’s no way to choose the right product or dose confidently.

    I am always suspicious when a brand doesn’t list ingredients. I assume it means the product is low quality and they are hiding it. But none of the brands I have seen list ingredients or even the mineral breakdown(!!) so they can’t be evaluated or compared.

    Thanks for any extra info 🙂

    1. Hi Stephanie,
      Thank you!
      Personally, I would put ShrimpLab and Brightwell on the second and third place. I have heard some rumors that ShrimpLab was made by the same people who created Saltyshrimp when they left the company. Although I do not know how true these rumors are.
      Best regards,

  7. Hi Michael,

    Could I use this to make Snello? I don’t know if it is aquarium safe, but if it is just calcium carbonate, and there is nothing else, it should be okay? Thank you!

  8. Hi! I’m just getting into aquariums, and I’m starting with a planted nano. Just got my first snails today, a pair of tiger nerites after letting the plants settle for about 3 weeks. Lots of algae for them to start on, and Buddy 1 immediately started to chow down.

    Currently, the water is quite hard as I started the tank from tap water. It’s had 2 water changes, a submersible heater to keep it steady. But, that’s not going to last forever.

    Before the end of the year, likely, they’re going to get a betta friend in the tank. Due to that, I’ll be keeping it at a ph of 7 and bettas prefer their water very soft. It’s going to be a gradual change, with regular monitoring and mixed water type changes to not shock my little buddies.

    What feeding/supplement schedule would you recommend? Are the veggie sticks or another thing listed in your article a good option on their own, with the occasional blanched fruit/veg, or would it be algae wafer bits supplemented with the high calcium treats?

    1. Hi Jodie,
      Gradual change will not chock them, but you already know that these water parameters are not good for Nerite snails.
      Again, you have just answered your own question – supplement them with wafers with high calcium treats.
      Will it be enough? Well, frankly saying, in the long run, I do not think so. They may survive but won’t be happy at all.
      Best regards,

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