Dropsy

Dropsy is an Bacterial infection, which puffs up the tissues, which intern makes the scales stick out, like a spiky style, also the fish will bloat out alot too.  Once most off the scales on the body "spike" out, then your fish will die, sadly :(  But if you catch it in time, when a few scales "spike" out then sperate it and give it it's medicine that you buy in pet shops, which is ANTIBACTIRIAL stuff.  Use as directed and keep a close eye on it, to see if it's scales flatten again and bloating goes down.