Agreed. Don't feed it at all. Up water changes and vacuum up that cyanobacteria.They're candy canes. The white is normal. I've seen them plenty with white stripes. It doesn't look like tissue recession cause they're pretty plump. Phyto isn't really going to help these guys. Try mysis or something like that. However I can see your trates or phosphates are off due to the cyano. I'd look into that before starting heavy feeding.