some depends on the attitude of your drawfs, i tried recently putting a flame and coral beauty in a 175g at the same time, it did not go well for the coral beauty, previously i had seven drawfs in the same 175g before my wife added a hippo tang as a suprise birthday present while i was working out of town which wiped out the whole tank with ick before i got home(this was almost 10 years ago before we got married and before she knew what she knows now about saltwater care..which is very close to the same then and now except DONT PUT ANYTHING IN THE TANK