Hard to see from the picture. Are you sure it's algae? I can't think of any orange algae off the top of my head. First thing that comes to mind is a sponge possibly.
There is really nothing you can do unless your prepared to rear the larvae. If you're interesting in raising clown fish there is a ton of information to be had on the net. If you're are not currently able or prepared to raise the fry then just let nature take it's course. The clowns may very well lay eggs routinely now.
The clown fish may eat them as well, especially if this is during their first couple spawns. No hermit or snail is getting anywhere near those eggs with a clown on watch.