Set up for crabs and fish

[DrH]

Hello .. I’m getting back to the hobby and resurrecting my 15 yrs old 70g tank. planning to add variety of crabs, a couple of fish, and star fish. However, some crabs need to breath air so any ideas how to set that up? I was thinking of leaving the tip if a rock out of the water. Any suggestions?

 

[Spare time]

What kinds of crabs? I can only thing of fiddler crabs as one that needs space out of the water.

 

[DrH]

Thanks for replying..I will take pics before acquiring them and post it.