Two fantail goldfish separated due to chasing

Hi, I'm new and have questions about my daughter's goldfish.I bought them about 3 yrs ago, not realizing their rapid growth. I moved them from a small tank to 10 gals in Jan 2013, then was forced to buy a 29 gal a week ago because one had pink areas on his fin. Right after the move, the pink began to vanish but signs of ich developed. (I am treating it), but that's when the healthy fish started chasing the sick one. I bought a separator and I'm wondering when I can remove it. It has been 4 days now since the separation. There is no sign of illness any more. I 'googled' this post:http://www.aquariacentral.com/forums/showthread.php?98145-Sexing-goldfish-(with-photos)! Both fish, especially the sick one, are developing tubercles, so I'm guessing they are both males. Anyway, I need to know how long to keep them separated. thanks

Yes, I was treating it with heat but have turned it back down as the new heater was making the temp too high even on it's lowest setting. Thank you very much for your reply. There is no sign of ich on either fish. The chaser is not male as there are no visible tubercles as I originally thought. Should I be concerned about mating? (researching the internet helps but I feel better asking the aquarium experts:goldfish

Thank you Sandybottom. The fish were purchased about 3 and a half to 4 years ago when they were very small. The female?(no visible tubercles) is the aggressor. She seems to pay a lot of attention to the divider. I think I need to remove the divider to check if they have settled down after removing the heater. I will remove the screen divider and observe them, then I can post my observations. thanks again!

I removed the divider and the chaser went crazy darting after the other with her nose at his tail. She chased him with increased vigor and urgency. I replaced the divider. I'm not sure what to do next....

The pursued fish keeps laying on the bottom of the tank. These are my 10 yr old daughter's fish and she is worried. Thanks

The male is the one being chased; he has perked up. I treated the ich for 8 days. I caught it very early and there are no remaining signs of ich. At first I treated it with salt and heat, then switched to Para Guard. Still not sure why the female is chasing the male. When I tried moving the divider she chased him with a kind of urgent high speed until I replaced the divider again.