Land hermit crabs or Aquatic hermit crabs?
Land hermit crabs need a tank about 2 foot long or bigger so they can wander around a bit. Put 1/2 -1 inch of beach sand or fine gravel on the bottom. Add some caves and wood/ rocks/ ornaments for them to climb on.
Have 2 containers of water, 1 sea water and 1 freshwater. Use water that is free of chlorine/ chloramine.
Have a container of dry food made from fish foods, a small amount of cornflakes and muesli, and add some fresh fruit and vegetables each day.
Don't feed them potatoes or onions or onion relatives.
Replace the fruit and veg, and water each day.
Do not have a coverglass on top of the tank because it can increase the humidity too much and cause fungal infections.
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Wash the tank out each week with tap water, and wash the sand and ornaments too. Drain the excess water out and then set it back up. The substrate will dry out over the next 24 hours and will be fine.
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Let the crabs out each day to walk around for 30 minutes or so.
Take them outside for a short time so they can get some sunlight but not too much. Avoid midday heat and take them out in the morning or afternoon.
Don't put the tank out in the sun though because it can heat up and cook the crabs or crack the glass. Just take the crabs out and let them wander around the backyard for a bit.
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Try to get small crabs because they are less likely to bite. Handle the crabs before you buy them and see if they are biters or if they are happy little vegemites that don't bite.
And get a few shells that are similar size and slightly bigger than the shells they are currently in. Res the shells on the substrate but have the shell opening facing up. The crabs will check them out and move into them if they like them.
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Aquatic hermit crabs live in marine tanks. Just set up a marine tank, cycle it and add some hermit crabs.
I'm gonna use that phrase now
