This is a question for those of you on here that have kept wild betta species before...what did you feed them? Would they only take live? Was frozen accepted? Did they even take pellet or flake at some point?
My coccina complex wilds really only like frozen/live foods with a preference for live. I did used to feed some of my F1 fish NLS small fish formula, but they never took it very enthusiastically and because they don't swarm to the surface when feeding, it makes it difficult in group set-ups to know if everyone is eating.
My mouthbrooders were much less fussy. My channoides, albimarginata, strohi, unimaculata, ideii and macrostoma all took pellets very eagerly. My stiktos pair also took pellets.
Personally I like to keep my fish on live/frozen foods because the pairs do share a tank and they do spawn quite frequently. I feel it keeps the fish in better conditions for spawning, and helps speed up the healing of damaged fins and scales.
I feed grindals, white worms, mosquito larvae (staple over the warmer months), blackworms, frozen brine shrimp and frozen bloodworms.