HCA: Hermit Crab Association

I've noticed that the HCA care sheet for Ecuadorians notes that they sometimes change colors in captivity. This has also been noted in other forum topics regarding E care, and seems to be treated as a normal occurrence.

However, I've noticed that Hermit Crabs for Dummies states that turning blue or green is a result of a carotene deficiency.

"Strawberry and Ecuadorian hermit crabs, in particular, suffer from carotene deficiency... Ecuadorian crabs that don't get enough carotene molt into blue or green. Washed out E-crabs are pretty, but as a pet owner, you are more concerned with their actual health than their appearance." -(p.51) Kelli A. Wilkins, 2007.

Krista Wilkin notes it as well on her own website (http://www.hermit-crabs.com/species.html).

"The color change is a direct result of their [Ecuadorians'] diet -- a crab that is not eating enough carotene will have a washed-out appearance after molting."

How accurate is this information? Are the color changes a result of diet? I haven't been able to find this information anywhere in the HCA forums. Sorry, most of my experience is with PPs. Es and other "exotics" aren't very common where I live.

I have no idea if any of that is true or how they would have verified the information. A lot of "common knowledge" back in the day was never scientifically verified.

In the wild younger (smaller) Es are blue and older (larger) Es are orange and even red. In captivity they will change fairly quickly from blue into more orangey shades no matter their age, usually within one molt. It may be diet related, but the few people who have managed to get theirs to hang onto the blue shades for an extended period of time (which is very rare) have UVB lighting so it may be more hormonal in nature.

I can't speak to non-Coenobita species, but I've combed through a lot of the scientific literature specific to Coenobita and havent run across any studies pertaining to carotene (or indeed colouration of exo at all) for compressus or perlatus.

If I had to guess, I'd bet this was extrapolated from something pertaining to another kind of crab - or else it could possibly be an assertion based on as-yet unpublished work (?) that the author had from some reasearcher... though 2007 was a while ago, even by publication standards, so I'd rather doubt it.

Are there any sources cited in this book? I kind of want to check out its bibliography now...



But yeah, I got nothing.

I have a couple of E's that have molted several times with me and grown from maybe 1/2-3/4" shell openings to 1.25"-1.5" shell openings and one of them has always had a blue tinge.

They get a really varied diet with a lot of fruits, vegetables and flowers as well as astaxanthin powder (a red/orange color enhancer) and even that doesn't seem to affect my E's coloring.



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That's not too big given that they wear oval openings. My smaller guys always had some blue left on them, usually along the body or inside the legs. It doesn't disappear completely for a while, they'll have brown or orange or yellow legs with bluish accents. It was only once they got into the 2" and above range that they lost all sign of the blue/green.

The first two was before and after one molt in small Es.

The third was a very large E that came that color from the wild.

Fourth was one of the original Es after a couple of molts.

Fifth was my jumbo E. He came that color and only got stronger after a molt. Instead of blue he was brilliant white on his underside.

Sixth was a freshly bought small E.

7-9 I consider that to be normal coloration for average (medium to large) sized Es, wildcaught or not.

10-12 are freshly caught smaller Es. Even though they were lemon yellow and lime green and slate blue they were showing signs of darkening.

The last two pics show how they often start the color change, darkening on the outer edges and still being bright on the inner surfaces.

One is in a turbo and the other a land fairy shell.

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Great pics as always Wodesorel!

LMBO - I'm not sure that I could even catch any of mine if I wanted to - those buggers are so fast! They let me watch them, but when the lid opens - they are GONE!!! I have three really large ones, and the others are miscellaneous sizes. I think my last count I had 10. My large ones are orange/tan with a little red. My other guys are brown/tan/orange with maybe a tinge of grey/blue on the insides of their legs. I've only seen them fully blue when I first got them or when they were really little.