20 gallon ok for coral banded?

[Charlie97L]

well, he's in my 58, and he's really going after my other fish, and my dad likes him a lot, and has been wanting a SW tank in his home office... would a 20 gallon be an ok size for a fairly large Coral Banded Shrimp? he'd be pretty much the lone occupant, other than some coral, and maybe eventually a meaner fish like a damsel, that i doubt would let him get away with much. so my questions are

 

-20 gallon big enough? i could go 25 easily, but 29 won't fit in the space.

 

-fish suggestions to safely cohabitate with an aggressive CBS

 

-would i be ok in using some of my current tank water and LR as starters for this tank?

 

thanks guys!