adding a second tang

[Keywest99]

I have a PBT that tore into a much smaller clown tang.(Bit his tail fin and shook him like a shark ripping off a chunk of tuna) needless to say even after keeping the lights off, the clown tang wouldn't come out of the corner and starved. Yes, I know tangs don't get along and find others as competitors for food, but did I make a mistake in size difference..PBT is 4", the clown was 1 1/2"? I still want to add another tang(Achilles) but don't want to throw money down the drain along with another dead fish. Any words of wisdom would be appreciated!! Bob