Whats wrong with my guppy?

i have tropical fish, and one of them is a little red guppy. i think he's really sick, his scales are lifting, a couple have fallen off. He's also gotten darker and goes up to the top and sticks his nose out of the water, i looked up on the internet and it sounds like that Dropsy or Malawi Bloat. It says it can be caused by to much protein, I do feed my black ghost knife bloodworms could it be that he eats to many of them and not enough flakes? I also have a silver shark, an angel fish, a golden coloured gourami he's got brown speckles on him but there normal, and 2 algae eaters. my neon tetra died a couple of days ago. could he have had the same thing as my guppy? is it contageous? What can i put in the water to make my guppy better that wont hurt the other fish?