Auratus are goldfish, basically. They look like goldfish, they act like goldfish, but they have a slightly higher level of intellience. Most of them are rather small.. the larger ones being 8-10" long, including their fins, and the smaller types being 5-6". They live in water, obviously, and they eat just about anything. This includes plants, smaller little creatures (not fish), pellets that you can give them, etc. Treat them like you would any other fish - they require about the same amount of care.
They are genderless. That doesn't really mean a whole lot now, but once breeding comes along (when there are enough parents), it will mean that any auratus can breed with any other auratus. You can treat your fish as one gender or the other, but it will not be put on the certificate or made official in any other way.
As with real goldfish, auratus are rather smart. They'll greet you when you go near them, be happy to see you, and eventually may learn a few tricks if you train them well. They're limited by the water they live in, as they can't just walk around and interact with you and go everywhere you go. (For more about the interaction aspect, see the RP post.)
Love your auratus. They're a lot better of a pet than many people think they are. So much personality from such a small creature is wonderful, and once you discover that, I'm sure you'll be very surprised and pleased to have such a nice friend.