what should i add to this set-up

Big Vine

Elite Fish
Feb 7, 2006
3,895
9
0
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Florida
#3
Ronin,

I haven't kept crabs before, but I've researched different crab setups a lot lately, because I was thinking about getting a crab setup going too.

Most sources recommend having sand in the tank, as the crabs usually love to burrow. Hiding spots, such as the rocks, are good too. Also...depending on the type of crab you're getting, brackish water is a must.
Use oceanic salt (I've heard from people who have had worse luck using regular freshwater aquarium salt---best to use "Instant Ocean" or something like that).

Also, having a small dish buried in the sand (above the surface of the water) and filled with regular, treated water (no salt) is important for allowing the crabs to re-equilibrate/re-adjust their "salt levels."
(sorry, I don't know the proper terminology here...that's just what I've read).

Having some plants would provide decent cover for the crabs as well.

Hope this helps.
Big Vine