Hi All. I'm sorry to write this here, but I don't have a lot of time to do research right now, and I was hoping somebody could point me in the right direction.

My older female rainbowfish, has been with me for over a year. I noticed a slight irregularily to her breathing (seemingly gulping) last night, but she ate fine. This morning, she is still doing it, and her gills are "sticking out" or inflamed. Her color is darker and she is less active...I can tell she is struggling. No going to the top of the tank, however, and ammonia and nitrite are both zero. Nitrates are roughly 10-15. All other fish are acting fine, even otos.

I removed her to QT bucket with aeration and put aquarium salt in the water, approx. 1t. per gal.

Some recent events in the tank: old (9years) australian rainbowfish died on Thursday...removed promptly, no sign of disease. water change of 45% on Friday. Two new boseman rainbows (juvies) added on Saturday night, both are healthy AFAIK. Water params tested just now, and listed above.

Thanks for helping me if you can...my two year old daughter has noticed my distraction and is now screaming/crawling all over me, and my older daughter needs to picked up from preschool and has a play date thing later. I am trying to juggle all of this. TIA.