Can i support more fish

there is 4 hammer corals and a small sebae, a few mushroom/pollyp collonies as well

 

Second that! Grammas are great! ;D

Concur with the others...if you really do not like the choices among the smaller fish you'll probably want to consider upgrading to a larger tank...good "larger" selections for your tank size would be a single Kole Tang, or one of the Centropyge sp. dwarf angels...perhaps a wrasse...HTH a little

 

I concur, get rid of the tang when it gets larger. Get smaller fish or get a bigger tank and turn that 55gal into your sump/fuge

 

i agree that you shoudnt really add another tang to a 55G. a tang shouldnt be placed in nothing smaller than a 75G. or it will outgrow it.

i dont think a tang can outgrow a 120 though.. ( maybe a naso) but im not sure about a regal tang.

 

if i i were to remove my regal, and white tail damsel... add my 405 canister and skimmer. could i then safely house a kole tang, my two clown, my butterfly, and perhaps another ?

 

well you can do the swap. from regal to kole but i wouldnt do both though.

 

The skimmer will help out a lot. The kole tang is a good choice, I have a yellow in a 55 and any tang will eventually outgrow that size tank. I would replace the regal with a kole and then, with the skimmer and such, add another fish. Keep in mind that the fish will grow, so many fish that start out small will grow to a nice medium size including clowns, damsels, gobies and wrasses. Those are also all very good choices for that size tank.