crabs dining on macro algae?

[Oakie]

had some unwanted macro algae growing on a rock in my SH tank. While I was doing some work on the tank, I took the rock out and placed it in my frag tank. Within the day, almost three quarters of the algae is gone - I have a yellow tang in there but doesn't seem interested. I have however noticed two hermits constantly on the rock - are they eating the macro algae?

[BLockamon]

Could be; what type of macro is it?

[Oakie]

hmmm.....good question. It's not familiar to me....looks like small clovers - clover is about 1/4" across and grown on a long strand with a clover every 1/4" or so. I'll try to google.

[drummereef]

Halimeda perhaps?