Hermit crabs are fascinating pets to have. Most of the aquarists get impressed by their ornamental color pattern and low maintenance and decide to add some to their tank. But after checking hermit crabs groups on the internet, I found out that all most all the beginners are struggling to figure out how many hermit crabs they should get. So today, I’ve decided to clear all the question marks regarding this topic.

Hermit crabs are social, and they love a company like ours. So, even if you are a beginner, you will have to get multiple crabs. How many hermit crabs you should get will depend on the species and size of crabs and also the size of your tank. I would recommend starting with three small hermit crabs in a 10 gallon tank.

In the rest of the article, I’ve discussed all the factors that you will have to consider to determine how many hermit crabs to get and how many crabs you can keep in a 20, 30, and 50 gallon tank. At the end of this article, you will have a definite answer to this question.

How Many Hermit Crabs Should I Get For My Terrarium?

There are a wide variety of hermit crabs with different colors and patterns. Seeing some lovely little creature crawling in the tank is fun. But if you are thinking of adding hermit crabs just as your clean craw, let me tell you before, they are not as active and handy as snails. They will do 30% of your work.

How Many Hermit Crabs Should I Get

But as I told you before, they are fun to watch, and on top of that, they don’t demand much care. Considering these facts, most aquarists wish to add some hermit crabs to their tank. But for beginners, it may be a little difficult to figure out how many hermit crabs would be the perfect number to start with.

See, when you are deciding how many hermit crabs to get, you’ve to consider several factors, for instance, which species you are getting, the size and age of your carbs, tank size, etc.

Let’s see all the considerable factors to determine how many carbs to get.

1. Carb’s Species & Size

There are over 800 species of hermit crabs in the world. Of them, two species are mostly seen as aquarium pets. They are purple claw crabs scientific name Coenobita Clypeatus and Coenobita Compresus.

Coenobita Clypeatus can grow up to 3 to 4 inches. They are active creatures and demand more space in the tank. In fact, some have been observed to cover 3km in a week.

So if you have a big tank setup, like 40-50 gallons, then you can get 3 adult Coenobita Clypeatus crabs with 6-8 small crabs. On the contrary, if you own a 20-30 gallon tank, you can get a single hermit crab. And of course, you can’t keep it alone. So you have to get 2 to 3 small Coenobita Clypeatus.

Hermit Crabs
Hermit Crabs

Don’t worry, Coenobita Clypeatus is social and peaceful. The larger one won’t attack your small crabs.

Now head towards the other popular carb Coenobita Compresus.

Coenobita hermit crabs are one of the small species. The average size of a Coenobita hermit carb is 0.47 inches. So you can get 4 to 5 cute little crabs for your 20 gallon tank.

If you’ve chosen other hermit crab species, then check their size and tank requirements.

2. Age Of The Carb

The age of the carb is an important factor in determining how many carbs to get. It’s obvious that aged hermit crabs would need some space than young ones. So if you are getting small hermit crabs, you can get half a dozen for a 20 gallon tank.

But in the case of the adult ones, you can get only one for a 20 gallon tank. Then you have to get some small carbs to accompany the large one.

3. Tank Size

To determine how many hermit crabs you can get, you have to consider your tank size first.

See, hermit crabs need socialization for their healthy growth. But it does not mean you can put a bunch of them in a small enclosure.

This will limit their freedom to move freely. Such situations give them suffocation and stress. You have to always make sure that you are not overcrowding the tank.

For example, if you have a 10 gallon tank, you can never go for two adult Coenobita hermit crabs. They demand more space. Here you can get 2 to 3 medium-sized hermit crabs. Coenobita Compresus would be a perfect pick here.

How Many Hermit Crabs Per Gallon?

This is the most asked question of newbie hermit crab owners. See, there is no rule of thumb.

How many hermit crabs you can keep per gallon depends on the size and species of your crab. If you have small-sized hermit crabs, then you can keep more of them in a small enclosure. But the large one would demand more space.

I’ve seen some aquarists recommending one crab per gallon. But I won’t support that. I think it’s quite impractical.

Even for the small-sized hermit crab, I recommend 3 gallons. For middle-sized hermit crabs, it would be 6 gallons, and for the large size, you have to keep at least 10 gallons of space.

Besides adequate water, there should be enough hiding places, decorations, and sand substrate. You can also add some small river pebbles and live rocks.

Hermit crabs like relatively dry and hard soil where they can easily burrow down.

How Many Hermit Crabs Per Gallon

Below, I’ve given discussed how many hermit crabs you can keep in a 20, 30, and 50 gallon tank. If you are a beginner, I would highly recommend checking out the following guideline.

How Many Hermit Crabs For A 20 Gallon Tank?

A 20 gallon tank is a great option to start with. Even if you have started with a 5 or 10 gallon tank, you have to upgrade it to 20 gallon within a year.

If you are keeping Coenobita Clypeatus and they are 1 inch in size, then you can keep 2 to 3 of them in a 20 gallon tank. You can also add 2 to 3 young Coenobita hermit crabs. They will live peacefully.

In proper care, aquarium hermit crabs can live up to 10 to 15 years. They will grow about two inches in the first 3 to 4 years. After that, they will grow one-third of an inch each year.

As they grow, they will demand more space. If you love keeping these pets, then it would be a smart move to start with a few crabs and save space for them for the future when they grow up.

On the contrary, if you start with a jam-packed 20 gallon tank, you will have to shift some to a new tank within a year as they will grow.

How Many Hermit Crabs For A 30 Gallon Tank?

In a properly decorated 30 gallon tank, you can keep two 2-3 inches hermit crabs with three to four 1-inch crabs. It’s important to mix some crab species and sizes because it allows you to keep more crabs and make the best use of your tank space.

As I mentioned above, only water quantity is not the only thing. You have to make all the necessary arrangements to ensure the healthy growth and long life of your crabs.

How Many Hermit Crabs For A 50 Gallon Tank?

In a 50 gallon tank, you can easily keep 3 adults Coenobita Clypeatus of 4 inches with 6 to 8 Coenobita Compresus. If you are just starting, then 4 to 6 medium-sized crabs with 6 to 8 small-sized hermit crabs would be a perfect combination.

After the above discussion, I think now, you have a definite number of hermit crabs that you should get.

Related Article: How Many Turbo Snails Per Gallon You Can Keep?

Care Tips for hermit crabs

As you are here to learn about how many hermit crabs to get, that means you are serious about owning hermit crabs. So here I’m giving a quick but comprehensive care guide for hermit crabs, from setting up the tank to ensuring their healthy growth.

  1. Hermit crabs need enough space to move around. So when you are setting up a tank for them, consider leaving adequate space for each of your carbs.
  2. Hermit crabs prefer sand substrate. In the wild, they are mostly found on the seashore near rocks and carvels. Add some sand, rocks, pebbles, and decorations at the bottom where they can dent during molting.
  3.  The temperature of the tank should be between 70-80 degrees Fahrenheit (20-15 degree Celsius).
  4. The humidity level should be between 70-80%.
  5. Hermit crabs are sensitive to copper and nitrate. If you have any cooper meditation in the tank, remove it first before putting crabs in the tank.
  6. As hermit crabs can’t live alone, keep at least 3 carbs together so that they can interact daily and stay happy.
  7. You can’t keep hermit crabs in any open tank as they tend to crawl over the tank. Remember to add a cover to the tank.
  8. Hermit crabs are nocturnal. They are mostly active at night. So always give them food at night. You can give powers like food, chopped veggies, and fruits.
  9. Give them food in non-metallic or ceramic containers.
  10.  Clean the tank regularly to avoid bacteria and other infections and diseases. Make sure you remove leftover foods every day. Otherwise, it can spread toxic substances into the water.

Final Thought

How many hermit crabs to get depends on several factors, such as the specie, size, and age of the crabs as well as the size and setup of your tank.

If you are a beginner, you can start with 3 to 5 small-sized hermit crabs. After keeping them for a while, if you see you are enjoying keeping hermit crabs, then you can add some more.

If you got a bigger tank, for instance 20, 30, or 50 gallon tank, you could get crabs according to the above suggestion.

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