Focus and kanaplex won’t help. You need to feed small amounts of food multiple times a day to try and build some bulk up. Feed as much as it will consume, at least three times per day.
I would put antibiotics in the water if you can (in a treatment tank of course) and then feed it very high fat/protein foods like mysids (you may need to dice them up small enough). You can use Kanamycin, just not in the food.
You should dose every 48 hours for a total of 3 doses. I’ve not used Rod’s food, but have heard good things about it.
Melafix is a botanical tonic, not a true antibiotic. I've not used it is a reef. It is supposed to be reef safe, but I've heard reports that it isn't always so. My main issue with it is that people use it as a medication, in lieu of accepted drugs and it really shouldn't be used in place of antibiotics.
