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The Blue Legged Hermit Crab

By February 5, 2017October 11th, 2017Crustaceans, Reef Critters

I talked before about hermit crabs in general explaining the function of the saltwater clean up crew. But this time, let’s take a closer look at the blue legged hermit crab.

The electric blue hermit

Blue Legged Hermit Crab

There are a couple of reasons why I would advise the blue legged hermit crab for your nano reef compared to other species, but the most important one is probably its size. Especially the dwarf “variaty” that doesn’t get bigger than 1 inch, but also the electric blue hermit with a maximum size of 2 inches.

If you’re a loyal Mister Nano Reef Instagram follower and you’re wondering what kind “Sheldon” (and Herbie, R.I.P.) is, he is part of the electric blue hermit (Calcinus Elegans) family, my favorites. They are a bit bigger and have blue legs with black banding instead of red banding like the dwarf species.

They have one claw that is a tiny bit bigger then the other but the difference is not as profound as with other species. Its bright complementary orange antennas really pop out and make it a treat for the eyes.

Another reason is their hunger for algaes and dead organic food together with their ability to sift sand. Which makes them very good cleaners and a great addition to your tank and clean up crew.

A thief in the night

But that beauty and usefulness can come with a price. As all hermit crabs, they use shells as a shelter for the vulnerable (and for predators very tasty) back part of their body. And especially the electric blue hermit is a sucker for beautiful shells. If this means there is still another hermit or snail inside of that shell, well that’s too bad. Indeed, they can be real A-holes. 🙂 In any case, provide enough (beautiful) empty shells in your aquarium and you will avoid a lot of problems.

It’s electrifying!

…and a bit crazy! You will want to get 2 of these for your nano reef as they thrive in company. (But take into account the above point that they can also get jealous of eachother’s shell.) I can assure you they will provide you with enough laughs for weeks and months. Just take a look at the videos below, where you see Sheldon exploring the tank and holding on to a shrimp he doesn’t really want to share but is clearly enjoying.

Foods and molts

Some other fact I would like to point out is that a lot of people consider hermits to be the perfect algae eaters, so they don’t consider to feed them some additional food. Please do consider them as any other critter in your tank, drop in a shrimp or piece of fish once or twice a week and they will be very greatful for it.

And last but not least… do not panic when you find a seemingly dead hermit in your tank. Why? Because it’s probably a molt. It does look like a real life hermit, but it’s 90% of the time just its old “skin” like the one you see here. We’ve all been there…

Any more questions about the blue legged hermit crab? Let me know in the comments!


Hermit Crab Molt

Join the discussion 7 Comments

  • Cristal says:

    This is fun information that I did not know. I don’t have a tank or marine creatures, but I’m thinking about it. I never thought about getting a hermit crab; I just always thought about fish. They seem like interesting companions.

    • Mister Nano Reef says:

      Thanks Cristal! If you need more information about them, let me know. It’s always better to be well informed before getting into the hobby 🙂

  • Kevin says:

    I love this site especially your background of the coral reef.Years ago I use to own a pet store and we had marine fish and the whole bit, one of my friends had a 350 gal set up at his home that he has neutered for 15 years.I also love the information you provide in your post top notch !
    best of luck !

  • Leeaura Zen says:

    WOW!! I had no idea they were such intriguing little buggers LOL!! Thanks for this!

  • Trex says:

    I’m trying to get a 5G jellyfish tank cycled and one way they said it could be done was to use a few Blue Legged Hermit Crabs. Got the salt water ready 32ppm added three crabs and TopFin nitrifying bacteria. But a few hours later they are all looking like they died. One is upside down and seems to be out of its shell the other two are pulled up into theirs. The tank is a circle made by Jelly fish art. It’s air supply is small since they do better in low oxygen environments – No idea what happened, did I drown them?

    • Mister Nano Reef says:

      I think you sufficated them, hermits need oxygen of course… still I wouldn’t put anything in a tank that’s freshly started.
      You can also not just put them directly into the thank they need some time to acclimatise… Let it cycle for a few weeks & then add critters one by one.

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