i have a tropical freshwater tank.I want to buy a goldfish .is it ok to do so? I am going to put it into a divided tank.

I believe not as a tropical tank is usually kept at a high temperature and Goldfish are cold water fish. I've always been told not to get the two mixed. I gave up all of mine to be able to keep guppies, which was easier on the filters and my peace of mind, as the water changing on a tank with 2 orandas was making me look like I had a full time fish keeping job. Also, Goldfish are horribly dirty fish. They eat and then poop out twice as much and that mixed in with the high water temps can't be a good thing. I think if you really want goldfish, you should either turn the tank into a cold water one or get a new tank that you can set up for your goldfish without endangering it or the other fish from your tropical tank. Also and most important, Goldfish need at least 10 gallons of water PER fish, all goldfish gurus I've read articles from agree on that one rule, even if they don't always agree on everything else. However you decide to do it, please do update your post : ) Happy fish keeping!