If you aren’t already you could try soaking the pellets in some tank water, a few drops of garlic guard might help too. Seems very odd for clownfish not to be eating, they typically eat just about anything I throw in the tank. Flake, pellet or frozen just mix it up and keep offering a different variety. They do tend to get bored if you feed them the same stuff repeatedly. If you have a decent clean up crew they should take care of any extra food just stick to small amounts.