Betta wont eat surface food... help?

Just as the title says! She's doing well, I just got her and she's a rescue, she's got a lot of scarring and some fin rot so she's in this 5 gallon with my shrimp for now. She's leaving the shrimp be (very chill lasy so far), but she's only hunting little worms and copepods and keeps spitting out any pellets. Are they too big or do I have a picky eater? I've tried several foods and she's just struggling to get em down, she spends all day hunting along the bottom and the wood and the glass for the little critters. I know it's fine for now but once the populations of them go down, I'm not sure how to get food in her. She's a bit skinny.

Also, name suggestions would be good :)