I have two seabe's, today I bought my 2nd which surprisingly wasn't bleached out when I bought it.
Seabe #1 however was bleached out. Here's what I did to bring it back to health and get some zooanthelle going: I fed it every 2 to 3 days with a shot of brine shrimp. It didn't always eat it, but what it didn't eat the fish did. In order to not pollute the tank too bad I didn't feed the fish that night if they ended up eating the brine shrimp. It took about a month and the seabe regained its natural coloring. Now I feed it maybe once a month or so (either brine shrimp or a piece of raw shrimp from grocery store). Sometimes it doesn't eat it, sometimes it does. That's just how it goes.

Just my two cents...