Well, I've discovered that Big Bert has some redness around her gills, I have no idea what this could be other than some kind of bacterial infection... I have maracyn two ready to go, but i just thought i'd post a pic to see if anyone had any suggestions as to what this could be... the other fish in the tank is fine. The redness is mostly on the side showing in the pic,but there is a tiny bit of redness on the other side as well, Bert's water conditions are where they should be and she is eating and acting fine as well. THanks soo much.
~Stasia

Hey Stasia,
Im not much help but i happened to lose my last two goldfish to the same thing you are desribing. I tried almost everything. Treatments from the petshop, salt, isolation from the other fish, change of food.
Thing that i found so wierd is my fish never seemed to have mis-comfort at all. They ate and swam the same the whole time until they died.
The only thing i could call it by the end was "fish leprosy" lol because my second one lost his fin before he died but it was mainly all redness which got worse and worse. Im guessing it was some kind of Internal Infection.
I will be really interested if anyone knows anything about this disease too.
I wish you good luck with Big Bert, hope you cure him.
Abz

I found this on a website I hope it helps:
RED STREAKS
Two reasons for red streaking, ammonia and/or nitrite spikes in the water or the water has really degraded. That means the gills are most likely to be fried and dark red. Using a harsh medication on fried gills is not a good idea and will stress the fish further. The only thing that helps in this case is water changes every two or three days for a while. And then the right sized tanks with gravel cleaning/water changes once a week.

The second is systemic bacteria infection and the gills would more likely be lighter red to pink. Antibiotic food and/or oxolinic acid is indicated along with water changes. Healthy, unstressed fish are quite resistant to bacteria. Unless a new fish has been added without quarantine.

http://puregold.aquaria.net/pg/disease/disease.htm

Gill flukes and other parasites can cause redness around the gills also. It would be nice if you could take a gill scrape and look at it under a microscope, then maybe you could ID what was wrong. Unfortunately, that's hard to do, but the only real way to tell what's going on.

Best of luck with your fish, I wish I could be of more help!

Laura

Hey guys, thanks for your responses... I went on and treated the entire tank with maracyn 2 last night, and today Bert already looks better! I"m so relieved... It's weird, I've never seen anything like this before, and since I havn't added any new fish to the tank, i don't see how it could be gill flukes. Anyways, I hope it clears up within the next few days. thanks so much!
~Stasia