betta fish still not eating

hi! i got my betta a week ago and he’s super active and looks happy. he wasn’t eating at all the first few days; he would look at the food and swim away. i tried feeding him again today and he nipped at the food but didn’t eat it. i’ve tried pellets and freeze dried blood worms but no luck :(( my water levels are good i test it almost every day. im not really sure what to do