When I first got my betta he wouldn't eat any betta food. I tried like two
or three different kinds of betta food (my mom had one and I had one
previously). He just died a few weeks ago (caught a disease from another
fish ) and he never ate betta food. I could only get him to eat normal
tropical fish flakes. You might see if, in the off chance, that's the case
with yours. It's worth a shot.

~Elizabeth