I'm not sure.I'm so sorry. What does he have?
The water parameters are good but he won't accept food.Sorry about this. I'd offer him treats & keep his water extra pristine.
Do fish like peas?Have you tried feeding him a pea?
Well, some do. My betta loves them. But, if a fish isn't eating then it could be constipated. Peas help with that.Do fish like peas?