Theyre fish, they do not get over weight like a human would.
Simply put, yes- theyre bloated. That's really the only thing they can be. They can be of large/stocky body, as some fish are, but they cannot be "over weight".
Having them jump is a bad habit (they may attempt to jump on their own) and doesnt provide exercise... again, theyre fish. Exercise would be living, swimming, all that- as per usual. Feed them less or fast them, and their stomachs will assuredly go down. Also, depending on your tank temp, bloating may occur. If a tank is too cold, their metabolism slows and should be fed less (though the heat issue needs to be addressed).