They're little filters that collect yummy things from the water.
I like to believe they are castanets though.
edit: And yes, sorry, salt water! It's a UK native marine tank. Live next to the beach so it's just a holiday home for them (have set it up with advice from gf's dad who is a marine biologist; not mixing storebought animals and being careful and good).
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stevierar, Tue 6 Jan 2015, 22:14,
Reply)
So did he come with a shell
or did you strew an assortment of potential homes around the tank, for him to pick from?
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thecrapgatsby isn't listening LALALALALALA, Tue 6 Jan 2015, 22:18,
Reply)
He's a deep sea hermit crab that was washed up in a storm on Weymouth beach,
gf's dad rescued him for me. In his shell. I go collecting every so often and pick up shells of various sizes to have in there; they like to switch and try on new ones. I only have him and a smaller 'hairy' hermit crab.
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stevierar, Tue 6 Jan 2015, 22:21,
Reply)
Wow I love that they try on new ones every so often!
"do my castanets look big in this?"
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thecrapgatsby isn't listening LALALALALALA, Tue 6 Jan 2015, 22:24,
Reply)
Whenever the big one changes shell,
the little one will immediately go and find a new one. I think perhaps in part due to what Fronds posted but these are very different crabs and there's plenty to choose from. I think he just gets jealous.
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stevierar, Tue 6 Jan 2015, 22:26,
Reply)