If you have .25 ammonia you’re not fully cycled, you’re in a mini-cycle. Stressed fish don’t eat as well and that combined with it being new is likely your problem.
Was it eating flake where you bought it? If so it might just be the ammonia and new environment stressing it out. If it wasn’t than it might still be getting used to the idea that flakes are food.
Trying a different food is a good idea but water changes are (nearly) free; so get rid of that ammonia first.
Edit: (if this is the same tank as your other thread, the 29 gallon that has only been running a couple weeks, it’s not really surprising your cycle has not settled yet. It can take much longer for a tank to really be stable)