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). \
Related article:
- Can Snails Live Without Their Shell?
- Snails and Shell Problems. Causes and How to Fix
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 snails (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
There are many options on the market nowadays (For example, Aqua Blue Wizard,Shirakura Liquid Minerals,Shrimp King Shrimp Minerals,Brightwell Aquatics,ShrimplabMinerals,GlasGarten). 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 snail keepers.
Chicken Eggshells Powder
Chicken eggshells consist of calciumcarbonate (~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).
1. 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
This 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)
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
Calcium 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
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 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 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 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
This 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
Excellent combination of ingredients and a 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.
Vegetables
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 rolein 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.
