Sick African Dwarf Frog?

Yesterday i bought two african dwarf frogs from a local pet store and they seemed healthy when i got them. One of them is darker in color, eats like a pig and always lazily floats to the top and swims "froggy style" or balances his toes on a leaf or something like that. i have another one which i am worried about. he is slightly lighter in color and there is a slight (as in barely noticeable when the belly is in complete view) reddening and swelling of the skin. I just fed then bloodworms a few hours ago, could that be it? also the one with a slight discolorations tends to stay at the bottom of the tank but still does moves around and do random poses. i removed all the chlorine from the water before i put them in and have kept the temperature at around 76-78 degrees. both frogs have eaten and i see poop on the tank floor,but sometimes they spit the food back out.

are they in the tank with anyone? is the tank filtered? did you cycle the tank prior to adding the frogs? what are your water readings and when was your last water change?

frogs are very messy eaters, any food they spit out or miss will need to be taken out pretty sharpish before it starts to mess up the water.

it could be that the ill-looking frog has an internal infection, or if the tank was uncycled, is being affected by ammonia poisoning. can you get a photo of him?