There are several types of danios: some natural, some developed by selective breeding. Gold and blue danios were produced through selective breeding, leopards are true, as are giant danios. It sounds like you're looking at giant danios... these are larger, about 2-3 inches. I've never seen these with leopard spots... The leopard-spotted danios are usually smaller, like the zebra danios.
Not sure if that helps, but you might want to check on these fish online to see which ones you saw in the store.
Danios are very hardy fish, so I wouldn't worry too much about their needs, as long as your water is fresh. They tend to like neutral water with moderate hardness, but do fine in soft and harder water.
is a blessing, not a disease.