Salt to Water Ratio for Hermit Crabs - Complete Guide

Salt to Water Ratio for Hermit Crabs – Complete Guide

Hermit crabs like to live in those surroundings that are a little bit salty. Whether they are terrestrial hermit crabs or captive hermit crabs, salted water is one of their main aspects of life. They start feeling bad and unhealthy if salted water is missing in their habitat. Here comes a question in the minds of aquarists and hermit crab keepers, “what is the exact salt to water ratio for hermit crabs?”

A mixture of 1 ½ tablespoons of sea salt and 1 cup of water is the recommended ratio of salt to water for hermit crabs. It means if you have 1 gallon of water, add 5 cups of sea salt to it. More importantly, don’t use iodine, tap water, or other chemicals.

Things like common salt and other water purifiers are harmful to the health of hermit crabs. The hermies live happily in salted water. But it’s essential to pay attention to the ultimate guide before creating an appropriate aquarium for your pet hermit crabs.

So, let’s explore the “Ins and Outs” of our topic. Here we go!

Salt to Water Ratio for Hermit Crabs

Do you know maintaining the correct salt-to-water ratio is vital for the well-being of hermit crabs in captivity? Generally, most aquarists prefer that a ratio of one tablespoon of marine salt mix per gallon of water is best for the saltwater pools for hermit crabs.

This mimics the saline levels of their natural habitats and helps regulate essential bodily functions, such as osmoregulation and exoskeleton hardening. However, some other researchers state that one cup of sea salt in one gallon of water is the right ratio. So, I think all of their suggestions about the exact salt-to-water ratio for hermit crabs are right according to their experience.

But I am going to be more specific. So, I am taking a few salt types and then suggesting how much quantity of that specific salt is good for how much amount of water for hermit crabs.

1.Cystal Sea Marinemix Bioassy Formula

Cystal Sea Marinemix Bioassy Formula is a trendy salt available online. You can purchase it and use it for preparing salt-to-water ratio for hermit crabs. The table that shows the correct quantity of this salt with water quantity is given below.

Cystal Sea Marinemix Bioassy Formula QuantityWater Quantity
1 ½ tablespoon8 oz / 1 cup
1 tablespoon16 oz / 1 pint
2 tablespoon32 oz / 1 quart
4 tablespoon64 oz / ½ gallon
8 tablespoon128 oz / 1 gallon

Interestingly, this salt took a longer time to dissolve as compared to oceanic. However, I found it useful for preparing a habitat for captive crabs.

2.Doc Wellfish’s Aquarium Salt

If you are using Doc Wellfish’s Aquarium Salt, don’t forget to add de-chlorinator drops, hot tap water (very small quantity), and then these salt crystals. Then, shake the water to dissolve crystals. You can wait one to two hours to fully dissolve the salt into the water.

Use the following prescribed salt-to-water ratio for your hermit crabs if you are using DW’s salt.

Doc Wellfish’s Aquarium Salt QuantityWater Quantity
1 ½ tablespoon8 oz / 1 cup
1 tablespoon16 oz / 1 pint
2 tablespoon32 oz / 1 quart
4 tablespoon 64 oz / ½ gallon
8 tablespoon128 oz / 1 gallon

So, you can see that the salt and water ratio for ‘Crystal Sea Marinemix Bioassy Formula’ is the same as for “Doc Wellfish’s Aquarium Salt.” Similarly, the salt-to-water ratio for the following salts is also the same.

3.Instant Ocean Salt:

Instant Ocean salt package states to use ½ cup of this salt for 1 gallon of water. However, many reports primarily focus on the highest metal concentrations. Still, many aquarists are using ‘Instant Ocean Salt’ for keeping hermit crabs.

4.Tropic Marin Sea Salt:

The instructions given on the “Tropic Marin Sea Salt’s package” are stated below:

  • 151 grams = 1 gallon
  • 151gms x .0353 = 5.33 ounces
  • 5.33oz/8(oz in a cup) = .66
  • 2/3 cup = 1 gallon.

Note: There are 31.68 or 32 tsp in 2/3 of a cup.

Similarly, there are other salts available online and offline. You can also use “ZooMed Hermit Crab Salt Water Conditioner Part II” and “Red Sea Salt.”

Do All Hermit Crabs Need Saltwater?

Salt to Water Ratio for Hermit Crabs

Absolutely Yes! All hermit crabs need salt water. In fact, if it’s a captivated hermit crab, it requires saltwater and fresh water. Moreover, here are the most important things to consider:

  • If you keep aquatic hermit crabs and land-dwelling hermit crabs, they flourish more in saltwater if their first habitat is freshwater. Mostly, these types of crabs require both types of water (freshwater + saltwater). So, the aquarists prepare two portions of water in their habitat, one of freshwater and the other of saltwater.
  • Most hermit crabs we see in aquariums are caught from the seas. So, we must understand that hermit crabs breed when they get salt water. That’s why the captivated hermit crabs rarely breed. Hence, we should give them salt water to spend their lives.
  • For your underwater hermit crab setup, don’t forget to handle the saltwater levels. If your hermit buddies share the tank with fish, make sure those fish pals can handle the salty vibes, too. I think you should keep it ocean-friendly for everyone’s happy underwater home.
  • Some hermit crab keepers state that their crabs died due to saltwater and freshwater or may be due to water exchange. I think, most of the time, they die due to temperature differences. For example, too hot or too cold water harms their health.

As you can see, aquarium enthusiasts like to keep hermit crabs with their fish and other tank mates. These crabs clean the tanks by eating algae and waste. That’s why our duty is to keep them safe by offering what we can do best for them.

Related article: How Long Can Hermit Crabs Stay Underwater? Exploring Their Aquatic Abilities

How to Mix Saltwater for Hermit Crabs?

Mixing salt-to-water ratio is very easy. Follow the following most straightforward procedure to do your job:

  • First of all, grab your suitable salt (anyone) and start creating the perfect saltwater solution.
  • Then, go by the gallon for precise measurements.
  • Use the appropriate tools to mix the selected salt and water.

If I would be in your place to create a mixture of salt and water for the very first time, I would use the following tools:

  • A vessel to hold the water (depends on my budget).
  • Appropriate salt (I would like to choose sea salt).
  • One gallon of filtered or bottled water – tap water is fatal to hermit crabs. However, if you use it, use it after boiling the water.
  • Water conditioner – it is required if you are filling an aquarium for marine hermit crabs.

After getting all of the above-mentioned pieces of equipment, I will follow the following procedure:

  • I’ll clean your empty container (vessel) and make sure no chemicals or residue linger.
  • Then, I’ll pour in the water.
  • If needed, I will try to add water conditioner and stir well.
  • Now, it’s time to toss in half a cup of salt, I will stir it until it’s clear with no lumps.
  • Let the water chill and settle to room temperature.
  • Apply the water to the aquarium or their bathing and drinking dishes. Easy peasy!

So, all done! I hope the procedure helps you create a soothing mixture of salt-to-water for hermit crabs.

Important Note: Terrestrial crabs? One mix is plenty. But if your hermit pals prefer aquatic living, get ready to repeat the process a few times to keep their underwater world just right.

Should we bathe our hermit crabs in salt water?

Yes, hermit crabs need salt water. They require it to regulate the saline content present in their bodies. Especially those hermit crabs that someone purchases from stores, they need a salt bath.

So, you should give them a salt bath if you think you are a responsible pet keeper. Otherwise, the other aquarium inhabitants will also get infected if the purchased crab has something wrong (diseases, pesticides, etc.).

If hermit crabs get saltwater baths, they smell the same as the other hermit crabs. Plus, the grime on them gets off, which is another benefit for newly purchased hermit crabs.


1.Can I use table salt in natural water for my hermit crabs?

No! Don’t make this mistake. Using table salt in water for hermit crabs is toxic to their health. This is because synthetic iodine is man-made, and it contains a lot of impurities and harmful chemicals.

I want to suggest you use food-grade sea salt. It is more refined and safe to use for hermit crabs. Moreover, if you add seaweed and seawater, it is more good because both contain natural salt.

2.I have maintained the salt-to-water ratio in my hermit crab tank. Still, they are dying. What to do?

Have you checked the pH level of the salt-to-water mixture? Maintaining the pH level of the aquarium is equally important as maintaining the salt-to-water mixture. Remember, the pH level must be between 7.5 to 8.4.


So, we had come to the conclusion of our guide about the “Salt to Water Ratio for Hermit Crabs.” We have learned that maintaining the right salt-to-water ratio is paramount for the well-being of hermit crabs in captivity. If we strike the correct balance, it will give a habitat to hermit crabs that mirrors their natural environment. Furthermore, it will promote essential physiological functions and overall health.

Last but not least, let’s start enhancing the longevity of our hermit crabs by following the guide given above. If you provide a captivating glimpse into their unique underwater world, they will thrive.