HCA: Hermit Crab Association

My crab Mango (male varibilis) who I’ve had for 6 years has been behaving rather oddly. For 2 weeks he hardly moved or ate. Then he started eating heaps and moving around. He has been leaving a shell drag trail all this time and the last few days he has been digging out hollows all over the place but not actually tunnelling. Sand is not compacted and he should be able to dig. I suspect he is ready and preparing for a molt but have never seen this sort of behaviour. First image shows a hollow behind the egg shell and 2 up the back under the leaves. Second is against front glass under the food shelf and 3rd image shows a hollow behind the shell shop and the salt pool.


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This is kinda normal crab behaviour, not even moulting behaviour, but just general goodly crab weirdness.

I know how shocking it is when they suddenly start doing something new to them! I've had my Rug for almost 4 years, and last month she dug herself out a permanent burrow for the first time. Actually excavated the sand and moved it far away from the opening. And then she dug down somewhere else to moult.

I have given up trying to understand them, and why they can develop a new phase out of nowhere

Yep it’s really weird coz I’ve never seen him behave like this. Hanging all day at the front of the tat with his face pressed up to the glass (almost) only change I’ve made is add an overhead vine. So perhaps he feels more protected now and is willing to hang out in the “open”


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The new vine does sort of make it more leafy and protected feeling.


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Dunno about your crabs but tank looks great! I need to add some green like that. Just reading here I’m not expecting plants to work but yours look like they are. I have pothos but haven’t added it yet. Thought it might be bad for them.


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And also I have a crab that I haven’t seen molt yet. And he or she has done exactly what yours is doing.


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jrleath wrote: ↑

Thu Jan 23, 2020 6:59 am

Dunno about your crabs but tank looks great! I need to add some green like that. Just reading here I’m not expecting plants to work but yours look like they are. I have pothos but haven’t added it yet. Thought it might be bad for them.


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Thanks for the compliment. This is only a plastic vine. Nothing live in my tank other than plants in my fresh water pool.

Renroc wrote: Thanks for the compliment. This is only a plastic vine. Nothing live in my tank other than plants in my fresh water pool.

Speaking of plants in FW pool, how are they travelling?

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. Some dieback as predicted but I suspect that may be due to being close to the heat mat. The hair grass is now in the fresh pool too and it is looking a bit brown. That could be from it’s time in the salt though.


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Id give the hairgrass a good trim, nearly down to the roots (like a couple of cm above the substrate) as its just dying. Once brownz leaves dont grow back green. Giving a good lop can also promote new growth.


The java underneath the surface looks like its doing well, hopefully it continues to do well.

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Haircut done. I'm no stylist though so I hope it doesn't mind .

Renroc wrote:Haircut done. I'm no stylist though so I hope it doesn't mind .

Haha, thankfully they dont have eyes, so we're the unfortunate ones that see!

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Awesome!!! May I ask how you light the plants? And I’ve been inspired by many planted tank hobbyists but Takashi Amano (ADA = Amano design aquascaping) and Dustins Fish Tanks. Dustin is more down to earth and makes it sound easy for beginners. Takashi who is dead now has really cool stuff. But if you buy his stuff you better be ready to come off the hip.

Anyway off subject a bit but I’m just curious about your lighting.


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I have a UVB tube above my tank. It is on a 12/12 cycleI don't know if any UVB actually gets into the tank but it lights it well. The room the tank is in also gets a good amount of natura light (but not directly on the tank) the plants have only been in a couple of weeks so time will tell if they go OK

Nice! I also have 2 UVB T8. (Exo Terra Reptile UVB 100). I don’t have anything blocking the UV. No glass , plexi or even screen mesh. But my little crab is eating the moss. There’s no way it can out grow even one crab. My other two crabs have been like statues for days, especially one. Starting to wonder about them.


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