There could be many reasons for why fish are acting strange. Don't rush to feed them anything, including pea or fish food.
I would like to know how did you put the fish into your tank? Did you put them in a plastic bag or a container and let it sit in the tank first? Did you add the water from the tank into the container little by little to let the fish get used to it? The fish do not like sudden change in water temperature or water chemistry. Any sudden large change can shock or even kill them.
Anyway. Try to do another partial water change of 30~50% without shocking the fish. Let the new water sit in the same room for at least half a day to have the same water temperature. You can skip feeding for a day or two no problem.
If possible, share a photo or two so we can actually see the problem.
