My pet turtle wont eat?

ok so i got this turtle at the carnival on saturday and i cant seem to get him to eat i have tried "tetrafauna reptomin" it says fir aquatic tutrles newts and froms it has mini pelets krill and baby shrimp she wont eat any of it so i tried lettuce and he hid under it but still didnt eat the lable on the food says feed them several times a day but hes alwyas got food floarting int he water and wont heat his water is truening cloudy because he wont eat his food am i doing some thing wrong is it suopsed t o float int he water or sit in the gravel and be dry?does he need a dish to eat from or maybe im just not seeing him eat he seems pretty active and its been 3 days since i brought him home shouldnt i have seen him eat by now ?? so heres about him hes about the size of a 50 cent peice hes a water turtle and he digs holes in the gravel ..dont kow if that matters but any ways please help