Fish Advice

[hawk]

Al,
That looks like Dictyota to me. If you go to the above link, they refer to it as brown or red antler shaped. Ignore the picture of the red branching algae but go to the highlighted 'Dictyota' link which shows a picture that is much more dense than yours, but if yours is anything like what I had, it will only be a matter of time before it grows from sparse to thick. In Bob Fenner's book The Conscientious Marine Aquarist, he shows a picture of Dictyota on page 132, it has the same "Y"shape as yours and mine but totally green. Mine was more on the pale side of green, some spots almost golden brown, but the exact same "Y"shape. Good luck