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As long as the fry aren't sick and their parents weren't sick, you could try. Did you try the garlic juice technique? Fasting procedures?
Fasting - Don't feed him for 2-3 days and see if he will eat. If he doesn't, take the food out. Repeat until he will finally eat his food.
Garlic Juice - Fast him for 2-3 days. If he won't eat, coat the pellets with garlic juice and feed. The juices will enhance the taste and smell.
What brand is your food? I recommend New Life Spectrum and Omega One. They're the best brands locally. Other good brands are Golden Pearls and Attison's.
Bad brands are Aqueon, Wardley's, Tetra, and Top Fin.
Good luck!