we use to have 3 goldfish in same large tank; one died after 3 days; the other died after few months so we are left with one who we think is a bit of a bully. 2 days ago we decided to add another goldfish to it's tank and it pushed this little new one around and would not let it eat it's food. to save any more harm coming to it, next day we bought a new tank and put the little fish in it. It's still not happy, floats around at the bottom of the tank, not swimming or eating food. I know it's just a goldfish but my daughter chose it and wants to know why it is not active; to be honest it looks half dead! will it perk up..?