Ed,
My falcula is about 5" also and is only a modest eater. I have had it 4 weeks. It started eating slowly and has gradually increased the amount it eats, but it still is not a strong eater. It lets most of the food drop to the bottom of the QT and then picks at it here and there. The fish came from BZA. I wanted a smaller fish (2-3") as I believe they adapt to captivity and aquarium food better than the larger ones.
The falcula started out eating NLS pellets (small) only. I think it started eating pretty quickly but not very much. I gave it some NLS flakes after 2 weeks or so and it quickly quit eating the pellets and ate only flakes (it may pick some pellets off the bottom of the QT). I have given it some small meaty foods (chopped clam, shrimp, scallop, and flounder) that it has started eating. At first, it ate the clam and shrimp but not the scallop and fish. It now eats the entire mix. It also eats Rods, some PE Mysis and a few live brine shrimp. I have a yln that only eats blackworms but the falcula ignores them. (Blackworms are supposed to entice butterflies, but 3 of my 4 butterflies won't eat them. Go figure.)
The fish looks for food when I approach the tank but it isn't an aggressive eater. Adding garlic or Selcon to pellets or flakes doesn't help. Perhaps that will change when it gets off meds (PraziPro and Cupramine, but I made sure it was eating first) and is in the DT. The way it is going, it won't surprise me if the falcula just quits eating for no apparent reason some day and dies, but I hope I am wrong.
Your fish concerns me if it hasn't eaten for a week. I would try live brine shrimp, live blackworms and a fresh clam on the half shell from the grocery store, plus some chopped fresh shrimp (from the grocery store) and mysis. If those don't work, try fresh mussel on the half shell from the grocery store and Cyclop-eeze from the fish store. Also flakes and pellets, both with and without garlic and Selcon. Please report back on whether it starts eating.
If the fish eats from a shell, some people have had success making a paste of various foods, freezing it in the shell, and putting the frozen concoction in the tank.